NOAA SEC Space Weather Bulletin #02-1: Major Solar Flare and Solar Radiaton Storm

SPACE WEATHER BULLETIN #02 – 1

2002 April 20 at 11:19 p.m. MDT (2002 April 21 0519 UTC)

A major solar flare occurred at 7:21 pm MDT (21/0151 UTC) on 20 April.

The resulting radio blackout reached the R3 level on the NOAA scale.
The flare was shortly followed by a strong solar radiation storm which

has reached the S3 level on the NOAA scale and is continuing in
progress at this time.

R3 radio blackouts result in widespread HF radio communication outages

on the dayside of the Earth and can also degrade low frequency
navigation signals.

S3 solar radiation storms can lead to single-event upsets in spacecraft

electronics, noise in spacecraft imaging systems, and reduction in the

efficiency of solar panels. Radiation storms also cause degraded HF
radio propagation in the polar regions and may be of some concern to
aircraft on polar routes.

Data used to provide space weather services are contributed by NOAA,
USAF, NASA, NSF, USGS, the International Space Environment Services
and other observatories, universities, and institutions. More
information is available at SEC’s Web site http://sec.noaa.gov or
(303) 497-5127. The NOAA Public Affairs contact is Barbara McGehan
at bmcgehan@boulder.noaa.gov or (303) 497-6288.