G2 (Moderate) Geomagnetic Storm of October 22, 1994

Name: G2 (Moderate) Geomagnetic Storm of October 22, 1994
Start: 1994-10-22T21:00:00.000Z
End: 1994-10-23T15:00:00.000Z
Location: Earth

October 22 to 23, 1994 · 18 hours

A G2 (moderate) geomagnetic storm began October 22, 1994, reached Kp 6+ and lasted 18 hours, with a daily Ap as high as 53; at that Kp the aurora may be seen from about 53 degrees geomagnetic latitude.

The Kp through the storm

Began Oct 22, 21:00 UTC, peaked in the block from Oct 22, 21:00 UTC, ended Oct 23, 15:00 UTC.

From 00 UT the day before to the end of the day after. Blocks in the storm are colored by level; the rest are gray.

The storm

Peak Kp: 6+ (6.33)
NOAA level: G2 Moderate
Duration: 18 hours
Highest daily Ap: 53
Highest 3-hour ap: 94
Rank since 1932: 846 of 4,139

How far south the aurora could have been seen

At Kp 6+ NOAA’s scales put the aurora’s reach at about 53 degrees geomagnetic latitude: 45°N in the central US, 44°N in the eastern US, 48°N in the western US and 54°N in northern Europe.

NOAA says a G2 storm’s aurora has been seen as low as New York and Idaho.

US cities within reach, the southernmost first

Saint Paul, MN 53.5° geomag.
Minneapolis, MN 53.5° geomag.
Spokane, WA 53.7° geomag.
Anchorage, AK 61.9° geomag.

4 US cities of 150,000 people or more sit at or poleward of that line. Low on the northern horizon under a dark, clear sky; not a record of sightings.

Tonight’s aurora forecast

Day by day

The daily Ap is the mean of the day’s eight three-hour ap values.

UT day	Daily Ap	Highest Kp that day
October 22, 1994	25	6+
October 23, 1994	53	6+

Flares before it

Peak (UTC)	Class	Region	Before the storm began
Oct 19, 23:13 UTC	M3.2	NOAA 7790	70 hours

The strongest M and X class flares GOES recorded from four days before the storm began to its end, the window in which a coronal mass ejection launched with a flare usually arrives. A flare in this list is context, not proof of the cause: many storms come from coronal holes, and many flares launch nothing toward Earth.

The storm before, Oct 7 The storm after, Oct 24 Every storm of 1994 The strongest on record This day in weather history Tonight’s aurora forecast

Sources

Kp and ap from GFZ Helmholtz Centre for Geosciences, Geomagnetic Observatory Niemegk, licensed CC BY 4.0: Matzka, J., Stolle, C., Yamazaki, Y., Bronkalla, O. and Morschhauser, A., 2021, The geomagnetic Kp index and derived indices of geomagnetic activity, Space Weather, doi:10.1029/2020SW002641; data doi:10.5880/Kp.0001. Storms, levels and aurora reach worked out by WeatherOverTime from those values and NOAA’s space weather scales. Definitive through August 31, 2026; later values are preliminary. Rebuilt 2026-09-26. Flares from NOAA NCEI’s GOES X-ray flare reports (1975 to 2017) and SWPC’s edited solar event lists, public domain; classes as NOAA recorded them at the time.