Idaho, 2002

Extreme Cold in Idaho, May 8 to 9, 2002

May 8 to 9, 2002 · NWS BOI · 3 events in 3 counties and zones

A very cold airmass invaded Southwest Idaho on the heels of a late spring storm. The combination of clear skies and light winds allowed temperatures to plunge well below freezing in the agricultural valleys during the early morning hours of May 8th and the overnight hours of the 8th and 9th.

Where it happened

Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

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The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
3

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS BOI wrote it up.

A very cold airmass invaded Southwest Idaho on the heels of a late spring storm. The combination of clear skies and light winds allowed temperatures to plunge well below freezing in the agricultural valleys during the early morning hours of May 8th and the overnight hours of the 8th and 9th. Temperatures reached 20 degrees in Mountain Home. Most observation sites recorded low temperatures in the mid to upper 20s. The hard freeze damaged fruit and field crops, including 1500 acres of sugar beets in Elmore County.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Boise, ID wrote its last area forecast discussion before the first event at May 7, 8:03 PM MST, 4 hours 57 minutes earlier.

Area forecast discussion, May 7, 8:03 PM MST, 4 hours 57 minutes before
SOUTHWEST IDAHO/SOUTHEAST OREGON AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE IDAHO
900 PM MDT TUESDAY MAY 7 2002

SATELLITE AND RADAR IMAGERY REVEALED A DECREASE IN THE NUMBER OF
SHOWERS AND CLOUDS.  HOWEVER, INTENSITY OF THE FEW REMAINING SHOWERS
WERE ON THE INCREASE.  LIGHTNING DETECTION EQUIPMENT HAD A STRIKE
JUST NORTH OF BOISE AT 830 PM.  THE EVENING SOUNDING AT BOISE
REVEALED MODERATE INSTABILITY IN A VERY DRY AIR MASS.  SO DRY THAT
MOST VALLEY DEW PINTS WERE IN THE TEENS AND A FEW IN THE SINGLE
DIGITS.  THE TREND IS OBVIOUS THOUGH,  SHOWERS SHOULD END BY
MIDNIGHT AND WINDS AND CLOUDS WILL CONTINUE TO DECREASE.  HAVE
ALREADY CANCELLED THE WIND ADVISORY IN MOST LOCATIONS AND THE LATEST
OBSERVATIONS INDICATE THAT THE REMAINING WIND ADVISORIES CAN BE
ALLOWED TO EXPIRE.  THE MAIN CONCERN NOW IS THE FREEZE FOR TONIGHT
IN THE LOWER VALLEYS  CONSIDERING THE DECREASING TREND OF WINDS AND
CLOUDS AND THE VERY LOW DEW POINTS, BELIEVE THE MINIMUMS TONIGHT
WILL DROP SEVERAL DEGREES MORE. WILL UPDATE THE CURRENT FORECAST FOR
TONIGHT AND GO WITH COLDER TEMPERATURES.

.BOI...FREEZE WARNING LATE TONIGHT/WEDNESDAY MORNING IDAHO ZONES
       12 14 16 AND OREGON ZONE 64.

EGGER

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

3 extreme cold/wind chill. Local standard time, as filed.

Extreme Cold/Wind Chill, Lower Treasure Valley

When
May 8, 1:00 AM MST to May 9, 12:00 PM MST
Where
Lower Treasure Valley forecast zone
Reported by
OFFICIAL NWS OBS.
Coordinates
43.746, -116.564 (the zone’s center; the record gives no point)

Extreme Cold/Wind Chill, Upper Treasure Valley

When
May 8, 1:00 AM MST to May 9, 12:00 PM MST
Where
Upper Treasure Valley forecast zone
Reported by
OFFICIAL NWS OBS.
Coordinates
43.129, -115.960 (the zone’s center; the record gives no point)

Extreme Cold/Wind Chill, Western Magic Valley

When
May 8, 1:00 AM MST to May 9, 12:00 PM MST
Where
Western Magic Valley forecast zone
Reported by
OFFICIAL NWS OBS.
Coordinates
42.672, -114.581 (the zone’s center; the record gives no point)

What these are

Extreme Cold/Wind Chill
Temperatures or wind chills at or below the local warning criteria, or cold that caused deaths.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Idaho in 2002Every state in 2002This day in weather historyWarnings in Idaho, May 2002

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5299887, 5299888, 5299889.