October 10, 2024: 22:00 Eastern Time
A severe magnetic storm commenced at 11:15 Eastern Daylight Time on October 10, 2024. The storm is ongoing. According to the NOAA Space Weather Prediction Center geomagnetic disturbance index, which classifies storms on a scale from G1 (minor)-G5 (extreme), the storm has, as of now, attained a G4 (severe) level of disturbance.
Storms of this intensity sometimes interfere with aeromagnetic surveys, directional drilling for oil and gas, satellite operations, GPS positioning and timing signals, and over-the-horizon radio communication, but they do not usually cause interruption of electric-power-transmission.
Aurorae are likely to be seen across much of the contiguous United States tonight.
In comparison to this even, the magnetic storm of May 10-12 attained a G5 level of disturbance, and the magnetic storms of June 27-28, August 11-12, and September 16-17 each attained a G4 level. Since we are presently in the ascending phase of the solar cycle, there is a high chance of several additional G4 storms occurring in the next year or two. There is also a good chance that another G5 storm will occur.
The present storm is being monitored at USGS magnetometer stations. Geomagnetic declination at College (Fairbanks), Alaska, has varied by 10.4 degrees, enough to be easily seen on a compass.
A conventional measure of magnetic-storm strength is the (low-latitude) disturbance index known as Dst. This index measures disturbance relative to quiet, non-stormy conditions. The USGS calculates a real-time Dst index useful for diagnosing the state of space weather during magnetic storms.
Soon after this storm commenced, Dst increased to 70 nT, indicating the development, in response to solar-wind pressure, of electric currents on the magnetopause (outer boundary of the magnetosphere). This was followed by a 1-hour period of positive Dst, after which the magnetopause currents apparently diminished, and the inner-magnetospheric ring current strengthened. These developments are indicated by the Dst declining to negative values. Dst is presently about -200 nT. The Kyoto Dst index has also attained about -200 nT. For comparison, the storm of May 10-12 attained a value of –422 nT. We do not yet know if the present storm will attain such a deep value in Dst.
The great storm of March 1989, which caused widespread interference to technological systems around the world, including power systems in the U.S. and a power blackout in Québec, attained a Dst value of -589 nT. The Carrington superstorm of September 1859, which caused widespread interference to telegraph systems, attained a Dst value of about -900 nT.
The USGS Geomagnetism Program operates 14 magnetic observatories across the U.S. and territories; the Program collaborates with the Albuquerque Seismological Laboratory in operation of variometers across CONUS; and it supports magnetotelluric surveys. The Geomagnetism Program disseminates magnetic data in real-time to governmental (both civilian and military), academic, and private institutions. Program scientists conduct research into the nature of geomagnetic variations for purposes of scientific understanding and hazard mitigation.
Jeffrey J. Love
For press enquiries, please contact Jeffrey J. Love (jlove@usgs.gov).
General enquiries about the Geomagnetism Program should be directed to Kristen A. Lewis (klewis@usgs.gov).
October 10, 2024: 22:00 Eastern Time
A severe magnetic storm commenced at 11:15 Eastern Daylight Time on October 10, 2024. The storm is ongoing. According to the NOAA Space Weather Prediction Center geomagnetic disturbance index, which classifies storms on a scale from G1 (minor)-G5 (extreme), the storm has, as of now, attained a G4 (severe) level of disturbance.
Storms of this intensity sometimes interfere with aeromagnetic surveys, directional drilling for oil and gas, satellite operations, GPS positioning and timing signals, and over-the-horizon radio communication, but they do not usually cause interruption of electric-power-transmission.
Aurorae are likely to be seen across much of the contiguous United States tonight.
In comparison to this even, the magnetic storm of May 10-12 attained a G5 level of disturbance, and the magnetic storms of June 27-28, August 11-12, and September 16-17 each attained a G4 level. Since we are presently in the ascending phase of the solar cycle, there is a high chance of several additional G4 storms occurring in the next year or two. There is also a good chance that another G5 storm will occur.
The present storm is being monitored at USGS magnetometer stations. Geomagnetic declination at College (Fairbanks), Alaska, has varied by 10.4 degrees, enough to be easily seen on a compass.
A conventional measure of magnetic-storm strength is the (low-latitude) disturbance index known as Dst. This index measures disturbance relative to quiet, non-stormy conditions. The USGS calculates a real-time Dst index useful for diagnosing the state of space weather during magnetic storms.
Soon after this storm commenced, Dst increased to 70 nT, indicating the development, in response to solar-wind pressure, of electric currents on the magnetopause (outer boundary of the magnetosphere). This was followed by a 1-hour period of positive Dst, after which the magnetopause currents apparently diminished, and the inner-magnetospheric ring current strengthened. These developments are indicated by the Dst declining to negative values. Dst is presently about -200 nT. The Kyoto Dst index has also attained about -200 nT. For comparison, the storm of May 10-12 attained a value of –422 nT. We do not yet know if the present storm will attain such a deep value in Dst.
The great storm of March 1989, which caused widespread interference to technological systems around the world, including power systems in the U.S. and a power blackout in Québec, attained a Dst value of -589 nT. The Carrington superstorm of September 1859, which caused widespread interference to telegraph systems, attained a Dst value of about -900 nT.
The USGS Geomagnetism Program operates 14 magnetic observatories across the U.S. and territories; the Program collaborates with the Albuquerque Seismological Laboratory in operation of variometers across CONUS; and it supports magnetotelluric surveys. The Geomagnetism Program disseminates magnetic data in real-time to governmental (both civilian and military), academic, and private institutions. Program scientists conduct research into the nature of geomagnetic variations for purposes of scientific understanding and hazard mitigation.
Jeffrey J. Love
For press enquiries, please contact Jeffrey J. Love (jlove@usgs.gov).
General enquiries about the Geomagnetism Program should be directed to Kristen A. Lewis (klewis@usgs.gov).