Abstract
Geomagnetically induced currents (GICs) due to space weather can impact electric power networks via transformer saturation, reactive power consumption, and increased total harmonic distortion. In the worst case, these can lead to widespread outages and damage to transformers. Investigating large geomagnetic storm events allows the power industry to better understand and mitigate the associated risks. Here we focus on the impacts in Alberta, Canada during the October 10–12, 2024 geomagnetic storm by modelling GICs in the ≥240 kV power network validated with transformer neutral-to-ground (TNG) GIC measurements. Despite the October 2024 storm being smaller than the May 2024 storm according to global storm disturbance indices, measured GIC exceeded 25 A/phase at three transformers in central Alberta and modelling suggests that the TNG GIC at some transformers in northeastern Alberta exceeded 30 A/phase, similar to the magnitude of the GICs seen during the May 2024 storm. For the October 2024 event, the cause of the largest geoelectric fields and largest GICs is spatially and temporally variable. Large events in northeastern Alberta were linked to the sudden storm commencement, with some large dusk-side events in southern Alberta being linked to a low-latitude substorm. The most spatially-extensive large geoelectric field event was associated with a large nightside substorm which developed over Alberta. In addition to GICs flowing at high voltage levels, the October 2024 storm also resulted in adverse technological impacts in northeastern Alberta at lower voltage levels. These included 34.5 kV capacitor banks and large 13.8 kV mine shovels tripping offline at industrial mining operations. The capacitor bank trips were likely due to increased total harmonic distortion due to transformer saturation from GIC at higher voltage levels, while the mine shovel trips may have been due to a unique failure mode related to induced current on long (∼10 km) low-current 30 V DC ground check circuits. To our knowledge, this is the first time that direct space weather impacts on mining operations have been reported in the literature.
1 Introduction
Space weather resulting from solar-terrestrial coupling can cause large disturbances to the Earth’s geomagnetic field. The resulting geomagnetic storms induce geoelectric fields in the ground which can generate a potential difference between grounded terminals of large man-made infrastructure such as electric power transmission networks, long-distance pipelines, and undersea cables []. In power transmission networks, the electromotive force from the geoelectric field in transmission lines results in low-frequency (<1 Hz) geomagnetically induced currents (GICs) which flow in transmission lines and transformer windings via the transformer neutral-to-ground (TNG) connection. Since the temporal variations of GICs are much less than the 50–60 Hz AC power system carrier frequency, they act as quasi-DC currents which can bias transformers into saturation leading to increased reactive power consumption, generation of harmonics, and transformer heating, among other problems []. If the GICs are large and sustained, they can overload networks resulting in voltage instability, transformer damage, and/or power outages.
On October 10–12, 2024 there was a large geomagnetic storm with a Dst index of −335 nT, the second largest storm of the current solar cycle after the May 2024 storm (e.g., [, ]). Although it was a smaller geomagnetic storm than the May 2024 storm in terms of Dst, and has therefore garnered less attention, it still had some notable global effects including strong ionospheric disturbances [–], red aurora at lower latitudes [], and potentially caused a premature satellite re-entry []. This storm also had characteristics which made it susceptible to generating large ground magnetic disturbances and large geoelectric fields (GEFs) [, , ]. Alberta is located at high geomagnetic latitude near the auroral oval and has significant datasets to characterize the ground geomagnetic disturbance using the CARISMA magnetometer array [] as well as extensive magnetotelluric (MT) measurements to characterize the ground conductivity [, ] (Figure 1). These both influence the resulting geoelectric field behaviour and therefore the GIC risk [–]. Via an ongoing industry-academia collaboration, we have developed an accurate DC-equivalent network model of the ≥240 kV transmission network. This model builds upon earlier work reported by Cordell et al. [], incorporates transformer-level details and expanded network resistance data based on information provided by the Alberta Electric System Operator (AESO) and transmission facility owners (AltaLink Management Ltd. and ATCO Electric Ltd.). As with the earlier model, the updated model can be used to compute data-driven GIC across the entire high-voltage (≥240 kV) electric power network in Alberta. Ongoing industry TNG GIC measurements at six transformer neutrals across the province allow for assessment of model performance and data validation.
FIGURE 1
During the storm, there were several key events with large geoelectric fields and GICs and, critically, these resulted in space weather impacts including 34.5 kV capacitor bank trips at one substation, and multiple DC ground check circuit trips on 13.8 kV industrial mine shovels in northeastern Alberta. These effects are notable in that they both occurred at voltage levels <240 kV and, to our knowledge, is the first documented case of mine shovels tripping offline due to space weather. Here, we present an analysis of this storm to highlight where and when large GIC were observed and modelled across the province and highlight the relationship between power network effects and space weather. We first focus on the methodology (Section 2) and then present specific impacts observed in northeastern Alberta (Section 3.1). We then zoom out to examine GIC observed and modelled at the province-scale (Section 3.2 and 3.3) and identify specific spatiotemporal patterns in the observed hazard. This observation motivates further discussion of the broader space weather conditions (Section 3.4) which led to these specific times of increased GIC.
2 Modeling methods
GIC modelling is often broken into two distinct steps. The first involves the calculation of the induced geoelectric field using magnetometer data and Earth impedance information. The second involves the calculation of the network level distribution of GICs in the power network using the modelled geoelectric field as input. The broad workflow is summarized in Figure 2.
FIGURE 2

Workflow diagram for data-driven GIC modelling. See text for abbreviations and details.
2.1 Geophysical step: geoelectric field estimation
In order to estimate the geoelectric field and GICs in the provincial power network during this storm, we use existing 1 Hz horizontal geomagnetic data from 11 sites from the CARISMA magnetometer array [
FIGURE 3

Map of magnetometer sites used in this paper for modelling geoelectric fields. Data sources from the CARISMA magnetometer array (www.carisma.ca), Natural Resources Canada (NRCan) magnetic observatories and United States Geological Survey (USGS) magnetic observatories.
The raw impedance tensor data at each location are not used directly because of noise and inconsistent bandwidth (e.g., some MT sites have valid data from 1 s to 20,000 s periods, while others have poor data quality and/or edited data points at periods >5000 s). Instead, the 3-D conductivity model from Wang and Unsworth [
After this procedure, the result is a set of spatially interpolated horizontal magnetic spectra and impedance tensors defined at each of the 411 MT site locations () on the same set of frequencies () (see Figure 2). The horizontal magnetic spectra and impedance tensor at each site are multiplied together in the frequency domain to solve for the horizontal electric field spectra at each location:where is the electric field spectra in V/m, is the impedance tensor in Ω, is the magnetic flux density spectra in Tesla, is the magnetic permeability of free space and , , and are all functions of and . Equations 1, 2 are optimized using page-wise matrix multiplication for each site where Z is and B is . The horizontal electric field can then be converted back to the time domain using the inverse Fourier transform to give horizontal electric field time series at each MT site location, in V/m. The entire procedure to compute the 2-day of electric data from the 2-day of magnetic data takes approximately 15 s on a standard laptop.
Note that there are several choices made during the implementation of this methodology. For example, we could compute the impedance anywhere in the 3-D model space, including on a regular grid, or along transmission lines. In other words, we can choose any , but here we choose . We also make choices about how to interpolate the magnetic field data (e.g., choice of specific interpolation method, as well as whether to interpolate in the time- or frequency-domain). We use the above methodology based on tests indicating that it appears to be very stable and results in the best fit between measured and modelled GICs while also allowing for decreased computational time. Specific inter-comparisons between other implementations of these methods is beyond the scope of the current paper.
2.2 Engineering step: GIC modelling
Once we have the geoelectric field components at various locations, we can include power transmission network information to compute GICs in the power network. First, we must compute the driving potential difference (i.e., the source e.m.f. that pushes current in the network elements). The geoelectric fields are spatially interpolated onto the 281 transmission line routings (L) for all transmission lines with nominal voltage at or above 240 kV in Alberta using 2 km segments (e.g., one interpolated geoelectric field every 2 km along the transmission line). This interpolation is done using the same q = Ad method as detailed above, with a total of >6500 transmission line query points. Following this, the potential difference (i.e., induced voltage, ) for each transmission line at each time step is computed by numerically integrating the interpolated horizontal electric field along each transmission line:where is the potential difference for the th transmission line at a given time step. Each transmission line routing is broken into segments of 2 km length, and are the north-south and east-west distances for the th segment, respectively, and and are the electric field components interpolated at the +1 segment nodes. The total calculation time for the potential difference simulation takes ∼15 s on a standard laptop.
After the potential difference is solved for, then Kirchoff’s Circuit Law (KCL) is used to solve the amount of current flowing in the ≥240 kV Alberta power transmission network, including to ground through TNG connections [
The current source for the ith edge is given bywhere is the resistance of the edge elements from and . Note that we set for all because the transformer winding distance is considered to be negligible relative to the geoelectric field. The nodal voltages can be calculated using the Modified Lehtinen-Pirjola method or Nodal Admittance Matrix (NAM) method [
3 Results and discussion
3.1 Space weather impacts
During the storm, there were several notable trips at capacitor banks in a substation in northeastern Alberta and at mine shovels in northeastern Alberta associated with large-scale industrial mining activities. Capacitor banks are located within substations and are designed to improve the power factor and reduce harmonics in the power network. They are particularly important in areas with large intermittent loads related to industrial operations. The mine shovels operate using 13.8 kV feeder cables up to 10 km long and use a 30 V DC ground check circuit to ensure adequate grounding of mobile mining equipment. During the storm, the DC ground check circuit tripped multiple times at multiple shovels, resulting in significant interruptions to operations. Figure 4 shows the ground magnetometer data from the CARISMA station at Fort McMurray (MCMU) [
FIGURE 4

Timing of space weather impacts on the power grid compared to (A) magnetometer data at MCMU and (B) modelled geoelectric field magnitude (|E| in V/km) at MT sites <150 km from the impact area. Vertical arrows show the timing of ground circuit trips at large 13.8 kV mine shovels (light blue) and the 34.5 kV network capacitor bank (black). (C) Shows the approximate location of the trips (white circle), the location of MCMU magnetometer (yellow circle), and the locations (white inverted triangles) where the calculated geoelectric fields in the bottom panel are from.
The substation capacitor banks experienced several trips between 15:15 UT on October 10 and 08:00 UT on October 11, coinciding exactly with spikes in geomagnetic activity and large, rapid spikes in the geoelectric field. This includes significant geoelectric field spikes exceeding 2 V/km at around 15:15 UT, 17:00 UT, and 23:00 UT on October 10, and around 05:00 UT and 08:00 UT on October 11. Two trips did not coincide with large spikes in the geoelectric field although they did coincide with a general period of increased geomagnetic activity between 19:00 and 20:30 UT on October 10. Note that the trips occurred on medium voltage (34.5 kV) capacitor banks which were not modelled in our existing GIC model. These trips likely occurred due to increased total harmonic distortion, which exceeded 40% during the storm. Quasi-DC GIC at 240 kV voltage level cannot flow to lower voltage levels for standard Yg-Yg windings, but harmonic distortion on the high side can be transferred across voltage levels [
The mine shovel DC ground check circuit tripped multiple times throughout the course of the storm, and each trip resulted in mine shovels being non-operational until reset. Nearly all mine shovel trips coincide closely with periods of increased geomagnetic activity and/or large geoelectric field spikes. This includes trips that coincide with the capacitor bank trips discussed above, such as a flurry of trips between 04:30 UT and 06:00 UT on October 11 during one of the largest 1000 nT deviations in the magnetic field observation at MCMU (Figure 4). However, there are also some trips which occurred during relatively less active periods during the storm (with associated geoelectric fields <2 V/km) between 00:00 UT and 03:00 UT on October 11. Despite the geoelectric fields being relatively small during this period, there was still quite significant geomagnetic activity at MCMU that may have resulted in localized geoelectric fields not well captured by the current MT site distribution and/or magnetic field interpolation. The mine shovels operate using 13.8 kV feeder lines which were also not modelled in the ≥240 kV GIC network model. The cause of these trips may be unrelated to GIC flowing at higher transmission voltage levels and may instead be caused by a direct trip on the low-current 30 V DC ground check circuit which is independent of transmission or distribution voltage level. Other mine shovel trips have been noted during other recent geomagnetic storm events (e.g., Nov 11–12, 2025, January 19–21, 2026), but not as many as occurred during the October 10–12, 2024, event. The storm-specific impact may be due to the length and orientation of cables which changes with time as the shovels and their cables are moved based on the requirements of the mine operations. Understanding the precise cause of these trips is beyond the scope of the current paper, but the data shows that they occur as a clear response to the local space weather conditions. As far as we are aware, this is the first documented case of long-cable mine shovel trips due to space weather reported in the literature and suggests an additional space weather impact which has not been previously discussed. This space weather impact could also affect other mining operations in other jurisdiction, but the causal connection between space weather and the trips may not have yet been made.
3.2 GIC measurements and model results
Beyond the specific impacts in northeastern Alberta, there was also notable GIC flowing in the transmission network across the whole province as indicated by both model results and the TNG GIC observations. Amongst the TNG GIC data being collected in Alberta, data are measured using a Hall probe device on the transformer neutral at a substation near Edmonton, AB, and at a substation ∼100 km west of Edmonton, AB (Figure 1) [
FIGURE 5

Hall probe TNG GIC measurements (red) and modelled TNG GIC at two substations in central Alberta.
Outside of the region in central Alberta where there are large TNG GIC measurements, there were also other notable large GIC events captured by the model during the course of the geomagnetic storm using the observed geomagnetic field time series as data input. Figure 6 shows the peak modelled GIC across the network during the entire storm interval. Figure 6A shows this in map view where the largest modelled total |GIC| flowing to ground at each substation during the entire storm period from 12:00 UT on October 10 to 23:59 UT on October 12 is plotted as colored circles scaled by their magnitude. This plot indicates regions that tended to have clusters of large GIC in central Alberta (a hub for 500 kV connections and significant power generation, and where TNG GIC measurements exist), and in northeastern Alberta (primarily 240 kV connections, but in a region without any TNG GIC instrumentation is installed). This pattern has been noted in previous publications for other geomagnetic storms [
FIGURE 6

Modelled peak absolute GIC at each substation in the network over the entire storm interval from 12:00 UT on October 10, 2024 to 23:59 UT on October 12, 2024. Left panel shows peak values in map view with circles coloured and sized by magnitude. Right panel shows peak values as a function of time with circles coloured by substation latitude.
Figure 6B shows the same peak GIC values flowed to ground at each substation during the entire storm interval as a function of time for each substation and colored by substation latitude. This clearly shows that there are distinct intervals of peak GIC activity across the province grouped into three clusters of time. The first occurs at ∼15:15 UT on October 10 and primarily impacts higher latitude substations, reaching >30 A/phase total to ground at the same substation where the 34.5 kV capacitor bank trips occurred. The second occurs at ∼02:00 UT on October 11 and primarily impacts lower latitude substations, but with lower GIC magnitudes <10 A/phase concentrated in southern Alberta. The third cluster occurs at ∼08:00 UT on October 11 and has a larger spatial scale which spans the entire province and impacts the majority of substations, reaching modelled peak values > 40 A/phase at Substation #1 where the measured TNG GIC was also largest in the province during this interval. These clustered times also correspond to peaks in the observed GIC (Figure 5). Capacitor bank trips in Figure 4 also occurred at ∼15:15 UT on October 10 and ∼08:00 UT on October 11, coinciding with the two distinct GIC clusters that impacted northern Alberta and all of Alberta, respectively. There were no capacitor bank trips that occurred around 02:00 UT as this cluster of peak GIC values primarily impacted substations in southern Alberta with lower overall GIC <10 A/phase.
Overall, these results show that data-driven GIC modelling results in relatively large GIC in the province with key clusters of activity both spatially and temporally. It is notable that, while the modelled GIC exceeded 30 A/phase in northeastern Alberta, these values are still relatively modest, and the storm itself was not extreme in terms of global indices, especially when compared to the May 2024 storm [
3.3 Model performance
The present version of the province-wide, high-voltage GIC model used here is seen to be a further improvement as compared to the results generated by the previous model reported by Cordell et al. [
It also appears that the present GIC model underestimates may not be solely related to inaccuracies of the network model since the same network model performed better for the May 10–12, 2024 geomagnetic storm at Substation #1 [
To further elucidate the causes of the discrepancies between the GIC model and measured TNG GIC discussed above in Figure 5, we show a comparison between the modelled geoelectric field and a measurement of the geoelectric field in Figure 7. The measured geoelectric field has been collected continuously at the Athabasca University Geophysical Observatory (AUGSO) located at (54.608°N, 113.642°W) using a magnetotelluric data logging instrument from Phoenix Geophysics. The modelled geoelectric field is taken from the nearest MT site (abt100) approximately 16 km away, calculated using geomagnetic data interpolated at this location using the magnetometer data from the sites in Figure 3. The measured geoelectric field at this location does not exceed 1 V/km, which is much smaller than the >2 V/km geoelectric fields seen in northeastern Alberta. This is likely because the measurement location is in a region with relatively thick (>1.5 km) sedimentary cover, whereas northeastern Alberta is located on the resistive Precambrian Canadian Shield. Such large variations in geoelectric field are expected based on local geology (e.g., [32, 33]).
FIGURE 7

Measured geoelectric field at Athabasca University Geophysical Observatory (AUGSO; 54.608°N, 113.642°W) and modelled geoelectric field calculated at the MT site abt100 (∼16 km away from AUGSO) calculated using interpolated magnetic field from the magnetometer data at stations shown in Figure 3.
The geoelectric field dataset from AUGSO can be used to validate the accuracy of the geoelectric field model at this location, and the direct geoelectric field comparison here improved agreement as compared to the comparison between the GIC model and TNG measurement. The geoelectric field model has correlation coefficients >0.80 and linear regression coefficients within the range 1.0 ± 0.2, when compared to the geoelectric field measurement. While this is only one location for an electric field comparison, the fact that the geoelectric field model agrees so well with the geoelectric field data could indicate that the discrepancies in the GIC model are mostly due to power network topology effects (e.g., exclusion of lower voltage levels), or perhaps arising from localized spatial variations in the electric field along power line segments.
Regardless of the specific causes of the discrepancies, further analysis of which is beyond the scope of the present study, the available TNG GIC measurements agree reasonably well with the GIC model given the large number of physical processes at play and the long chain of events from sparse ground magnetic field data, to calculated geoelectric field from a geophysical conductivity model, to network parameters to GIC. The modelling challenge is evidenced by the overall accuracy and prediction efficiency which other GIC studies have been able to achieve (e.g., [34, 35]), some of which require scaling factors >2 to adjust modelled magnitudes (e.g., [36, 37]). Based on the agreement between the modelled and observed TNG GIC during this storm, similar comparisons for the May 2024 superstorm [
3.4 Space weather drivers
Understanding the broader space weather drivers for these key events which caused clusters of more intense GIC and coincident with trips on capacitor banks and mine shovels is important to better understand the causes of specific GIC risk during the October 10–11, 2024 storm. Although the connection to the solar wind-magnetosphere coupling processes is not the primary focus of this paper, we present a brief overview of some of the key aspects in this subsection. The solar wind conditions (interplanetary magnetic field and proton density), mapped to the nose of the magnetosphere from the OMNI dataset (https://omniweb.gsfc.nasa.gov), and its connection to ground magnetic field data and magnetic field variations at selected ground magnetometers in Alberta are shown in Figure 8 over the entire storm interval from October 10–11, 2024. The early part of the storm resulted in sustained, large ground magnetic field variations and rapid dB/dt which were primarily concentrated at northern Alberta sites (FSMI, FCHP, MCMU), a period which also coincided with low-voltage capacitor bank trips and mine shovel trips in northeastern Alberta. This period was associated with rapid variations in the interplanetary magnetic field (IMF), as well as an interval of enhanced solar wind density [
FIGURE 8

Space weather conditions during the October 10–11, 2024 geomagnetic storm. (A) Z-component of the Interplanetary Magnetic Field (GSM coordinates); (B) Solar wind speed; (C) Solar wind proton density, all from OMNI and mapped to the magnetopause nose; (D) Relative horizontal ground magnetic field for six selected CARISMA magnetometer sites in the study area, shifted on vertical axis for display purposes; (E) The relative rate of change of the horizontal magnetic field (db/dt) at the same CARISMA sites, shifted on the vertical axis for display purposes. Vertical black arrows indicate times of interest; see text for details. Note that 18 magnetometer sites were used for the interpolation to compute the geoelectric field, but only the six stations in Alberta are shown here. All times are UT.
3.4.1 Sudden storm commencement (15:15 UT Oct 10)
Figure 9 shows the geoelectric field and GIC modelled at 15:15:42 UT on October 10, 2024. This corresponds to the time of the sudden storm commencement (SSC) seen clearly in the solar wind data and associated with the arrival of the sharp density increase and increase in magnetic field seen in Figure 8. The SSC did not induce especially large geoelectric fields or GICs at latitudes <55°N in Alberta, but it did induce large geoelectric fields and GICs primarily concentrated at higher latitudes. A similar pattern was seen in Europe, with SSC driving the largest geoelectric fields at around 65° MLAT in Scandinavia (a similar magnetic latitude as seen here) [38]. The SSC for this storm was also much larger than the SSC for the May 2024 storm, and which has been attributed to an oblique angle of incidence for the incoming interplanetary coronal mass ejection as it interacted with the magnetopause [
FIGURE 9

Map view snapshot geoelectric field model (left panel) and substation GIC (right panel) at the time of the SSC at 15:15:42 UT on October 10, 2024. For GICs, blue is GIC flowing out of the ground and red is flowing into the ground, with the colour and circle size indicating the magnitude of the GIC at each substation in the model.
From a space weather hazards perspective, the SSC event was very rapid and, as observed in ground magnetometers, lasted less than 2 minutes. We use 1 s cadence magnetometer data in the GIC modelling presented here which is able to accurately capture this rapid SSC. It is worth mentioning that 1-min sampled magnetometer data would not accurately capture the induced geoelectric field or GIC resulting from this SSC event [39]. This SSC event resulted in the largest calculated geoelectric fields in the province throughout the entire storm interval, exceeding 16 V/km at 1 MT site location, and 10 MT site locations exceeding 2 V/km in northeastern Alberta. However, because it was more localized, it did not drive significant GIC across much of the province, with the model showing only a handful of substations having GIC >10 A/phase, all located in northeastern Alberta. Note that there were also six sites with large geoelectric fields in southwestern Alberta and southeastern British Columbia >2 V/km due to extremely resistive Cordilleran geology, but these were not near the ≥240 kV Alberta power network and do not impact the space weather hazard in Alberta, although they may have importance for the BCHydro power network.
3.4.2 Localized GIC event (01:50 UT Oct 11)
A second event resulting in peak GIC in southern Alberta was associated with a localized substorm at approximately 01:50 UT on October 11 (19:50 MLT on October 10). This was the first in a sequence of substorm events each approximately 3 h apart at ∼02:00, 05:00 and 08:00 UT. This event is notable because it initiated at lower latitudes <52°N in Alberta, as shown in Figures 8, 10. The more northerly magnetometers did not show any notable geomagnetic disturbances for this event, while more southerly stations did, and this results in more pronounced geoelectric fields and GIC in southern Alberta only. The event was also notable as it occurred in the local dusk sector. While this event did not result in particularly large GIC (<10 A/phase), it did correspond to the time of the largest peak GIC at many substations in southern Alberta (Figure 6). This event highlights that large storms which push the auroral oval to lower latitudes can result in substorms with onsets at lower latitudes. This has been previously noted for the May 2024 storm in Alberta [
FIGURE 10

Map view snapshot geoelectric field model (left panel) and substation GIC (right panel) during the lower latitude substorm event at 01:51:32 UT on October 11, 2024. For GICs, blue is GIC flowing out of the ground and red is flowing into the ground, with the colour and circle size indicating the magnitude of the GIC at each substation in the model.
3.4.3 Regional GIC event (08:00 UT Oct 11)
Finally, the third event was much larger in scale, with GIC impacts spanning the entire province. This event occurred around 08:00 UT on October 11 (02:00 MLT) as shown in Figure 11. This event was a more typical nightside substorm event in Alberta at this time, and resulted in some of the largest GICs across the province with four substations exceeding 30 A/phase. This event also coincided with both 13.8 kV mine shovel trips and 34.5 kV capacitor bank trips in northeastern Alberta (Figure 4). The largest geoelectric fields during this event exceeded 1 V/km across much of the province with a maximum calculated geoelectric field magnitude of 6.8 V/km in northeastern Alberta. It is also notable that the geoelectric fields were oriented mostly unidirectionally, primarily north-south across much of the province during the sustained electric field pulse associated with this event. The north-south geoelectric field direction during this pulse was oriented such that it resulted in strong coupling with the longest transmission lines in Alberta which tend to have a similar geographic orientation. This highlights that the common perception that the overhead electrojet during geomagnetic storms is dominated by east-west oriented ionospheric current systems leading to predominantly east-west aligned geoelectric fields is an oversimplification of real storm-time dynamics. As discussed in detail by Parry et al. [
FIGURE 11

Map view snapshot geoelectric field model (left panel) and substation GIC (right panel) during the regional scale event at 08:00:37 UT on October 11, 2024. For GICs, blue is GIC flowing out of the ground and red is flowing into the ground, with the colour and circle size indicating the magnitude of the GIC at each substation in the model.
The analysis presented here highlights that different space weather drivers can result in multiple, distinct intervals characterized by large GICs throughout a single geomagnetic storm, and that these drivers can have complex spatiotemporal patterns. No single event or driver is responsible for the largest GIC at every location in the province during this geomagnetic storm. Furthermore, relatively localized and variable geoelectric fields are capable of driving large GICs only in specific parts of the network (e.g., the SSC only strongly influenced northern Alberta, and the lower latitude substorm only influenced southern Alberta). Only one of the events considered here involved large, relatively unidirectional geoelectric fields across the whole grid, and even then, the direction of the geoelectric field was not as expected from simplistic assumptions of drivers arising from predominantly east-west ionospheric current systems. GIC risk assessments which make a variety of such simplifying assumptions may therefore not adequately capture the full complexity of the associated hazard, and may be unable to accurately quantify the associated risk.
4 Conclusion
This work uses the example of the October 10–11, 2024 geomagnetic storm and a model of the high-voltage Alberta power network to assess the GIC impacts associated with this large storm. Significantly, we also report on a number of operational anomalies which occurred during this storm, including capacitor bank trips which occurred on the lower voltage (34.5 kV) side of a substation in northeastern Alberta, as well as operational anomalies which occurred at large-scale mining operations in northeastern Alberta related to long (∼10 km) DC ground check circuits for large 13.8 kV mine shovels, and resulted in significant interruptions to mine operations. The capacitor bank trips and mine shovel trips coincided with periods of intense geomagnetic activity and large induced geoelectric fields >2 V/km, demonstrating a clear correlation with space weather. To our knowledge, this is the first reported case of space weather impacting DC ground check circuits on mine shovels and may be of relevance to operators of industrial equipment in other jurisdictions, especially those operating in areas prone to large geomagnetic disturbances and large geoelectric fields. Both the capacitor banks and mine shovel trips occurred at lower voltage levels <40 kV, highlighting the need for more integration between HV and UHV GIC modelling and LV distribution and end-users.
In terms of the GIC response in the Alberta high voltage network, Hall effect transformer neutral-to-ground (TNG) measurements of GIC indicate that GIC reached magnitudes >25 A/phase in transformers in central Alberta. The data-driven GIC model uses dense magnetometer and magnetotelluric datasets to estimate GIC in network elements and suggests GIC values > 30 A/phase in northeastern Alberta although no TNG GIC measurements were present in that area at the time. While the discrepancies between measured and modelled GICs at locations where measurements were available are minimal, we show how continuous geoelectric field measurements can be used to further validate the model. In our case, the geoelectric field model agrees very well with measured geoelectric field from the Athabasca University Geophysical Observatory (AUGSO) in central Alberta. We hypothesize that the largest source of error in the present model is that it is assumes no GIC in the <240 kV elements of the network. The continuous geoelectric field measurement from AUGSO did not exceed 1 V/km, but modelled geoelectric fields exceeded 10 V/km in some locations, particularly in northeastern Alberta where the underlying ground conductivity acts to enhance the induced geoelectric field. Such discrepancies highlight the value of additional geoelectric field measurements, especially in northeastern Alberta where predicted geoelectric fields are largest but where conductivity models are more poorly-constrained by sparse magnetotelluric measurements.
Finally, we highlight the spatial and temporal variability of real geomagnetic storms by analyzing discrete intervals of time associated with clusters of large GIC. The October 10–12, 2024 storm had an unusually strong sudden storm commencement at ∼15:15 UT on October 10 which resulted in large calculated geoelectric fields, concentrated in northeastern Alberta, and which exceed 15 V/km. This SSC event also coincided precisely with the times when the first 34.5 kV capacitor bank and 13.8 kV mine shovel trips were noted. Another event at 01:50 UT on October 11 impacted only southern Alberta and which we associate her with a lower latitude substorm, even though Alberta was located on the dusk flank at the time. Finally, the largest substorm at ∼08:00 UT occurred when Alberta was just post-midnight local time, and which was seen to impact the entire province. Although it did not generate the largest localized geoelectric fields, it did generate the most spatially-extensive period of large geoelectric fields which spanned the entire province, resulting in large GICs at many substations across the province within a short 10 min interval.
Statements
Data availability statement
The datasets presented in this article are not readily available because GIC and network data are considered Critical Energy Infrastructure Information (CEII) and protected by NDA. CARISMA geomagnetic data is publicly available at carisma.ca. NRCan and USGS geomagnetic data are available at SuperMag repository (https://supermag.jhuapl.edu/; [
Author contributions
DC: Investigation, Funding acquisition, Methodology, Conceptualization, Writing – review and editing, Visualization, Validation, Formal Analysis, Software, Writing – original draft, Data curation. HP: Visualization, Funding acquisition, Writing – original draft, Data curation, Investigation, Writing – review and editing, Conceptualization. RM: Investigation, Resources, Validation, Data curation, Writing – review and editing. SG: Resources, Data curation, Writing – review and editing, Validation, Investigation. MAC: Data curation, Writing – review and editing, Investigation, Validation, Resources. MC: Resources, Writing – review and editing, Data curation, Validation, Investigation. SD: Resources, Data curation, Writing – review and editing, Investigation. RH: Investigation, Writing – review and editing, Data curation, Resources. IM: Project administration, Writing – review and editing, Supervision, Conceptualization, Resources, Funding acquisition.
Funding
The author(s) declared that financial support was received for this work and/or its publication. This work was carried out as part of the ongoing Natural Science Engineering Research Council (NSERC) Alliance Project (#590102) with contributions from NSERC, AltaLink Management Ltd., ATCO Electric Ltd., and the Alberta Electric System Operator (AESO). The funders were not involved in the study design, collection, analysis, interpretation of data, the writing of this article, or the decision to submit it for publication. IRM and MC are supported by a Discovery Research Grants from NSERC. CARISMA is operated by the University of Alberta, funded by the Canadian Space Agency as part of the GO Canada program. Athabasca University Geophysical Observatory was funded by the Canada Foundation for Innovation (CFI).
Acknowledgments
Thank you to Canadian Natural Resources Ltd. (CNRL) and Syncrude Canada Ltd. for providing capacitor bank trip and mine shovel trip data. Thank you to the AESO, AltaLink Management Ltd., and ATCO Electric Ltd. for providing detailed network information. Thank you to AltaLink Management Ltd. for providing GIC data. Thank you to Martyn Unsworth for providing the 3-D conductivity model and all those involved with magnetotelluric data collection. Thank you to Andy Kale and the CARISMA team for the ongoing operations of the CARISMA magnetometers, funded by the Canadian Space Agency. Thank you to NRCan and USGS for maintaining and operating the magnetic observatories used in this work.
Conflict of interest
Author RM was employed by AltaLink Management Ltd.
Author MA was employed by ATCO Electric Ltd.
Author SD was employed by Canadian Natural Resources Ltd.
Author RH was employed by Syncrude Canada Ltd.
The remaining author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Generative AI statement
The author(s) declared that generative AI was not used in the creation of this manuscript.
Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.
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Summary
Keywords
geomagnetic storm, geomagnetically induced currents, modelling, power networks, space weather
Citation
Cordell D, Parry H, MacMullin R, Gao S, AC M, Connors M, Desai S, Holland R and Mann IR (2026) Effects of space weather on the electric power network and mining operations in Alberta, Canada during the October 10–11, 2024 geomagnetic storm. Front. Phys. 14:1832129. doi: 10.3389/fphy.2026.1832129
Received
16 March 2026
Revised
08 April 2026
Accepted
13 April 2026
Published
28 May 2026
Volume
14 - 2026
Edited by
Denny Oliveira, University of Maryland, United States
Reviewed by
Soren Subritzky, University of Canterbury, New Zealand
Liejun Wang, Geoscience Australia, Australia
Updates

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Copyright
© 2026 Cordell, Parry, MacMullin, Gao, AC, Connors, Desai, Holland and Mann.
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Darcy Cordell, dcordell@athabascau.ca
Disclaimer
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.