G1 (Minor) Geomagnetic Storm of January 31, 1984

Name: G1 (Minor) Geomagnetic Storm of January 31, 1984
Start: 1984-01-31T15:00:00.000Z
End: 1984-01-31T18:00:00.000Z
Location: Earth

January 31, 1984 · 3 hours

A G1 (minor) geomagnetic storm began January 31, 1984, reached Kp 5 and lasted 3 hours, with a daily Ap as high as 23; at that Kp the aurora may be seen from about 60 degrees geomagnetic latitude.

The Kp through the storm

Began Jan 31, 15:00 UTC, peaked in the block from Jan 31, 15:00 UTC, ended Jan 31, 18:00 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: 5 (5.00)
NOAA level: G1 Minor
Duration: 3 hours
Highest daily Ap: 23
Highest 3-hour ap: 48
Rank since 1932: 3,774 of 4,139

How far south the aurora could have been seen

At Kp 5 NOAA’s scales put the aurora’s reach at about 60 degrees geomagnetic latitude: 52°N in the central US, 51°N in the eastern US, 54°N in the western US and 61°N in northern Europe.

NOAA says a G1 storm’s aurora commonly visible at high latitudes: northern Michigan and Maine.

US cities within reach, the southernmost first

Anchorage, AK 61.9° geomag.

1 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
January 31, 1984	23	5

Flares before it

Peak (UTC)	Class	Region	Before the storm began
Jan 30, 04:38 UTC	M2.9	NOAA 4399	34 hours
Jan 31, 07:33 UTC	M1.7		7 hours
Jan 31, 13:00 UTC	M1.2	NOAA 4397	2 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, Jan 29 The storm after, Feb 2 Every storm of 1984 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 2026-09-24. 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.