Heavy Snow in Idaho, December 4 to 5, 2001

Name: Heavy Snow in Idaho, December 4 to 5, 2001
Start: 2001-12-04T22:00
End: 2001-12-05T09:00
Location: Idaho

December 4 to 5, 2001 · NWS BOI · 2 events in 2 counties and zones

A strong Pacific storm brought between 4 and 12 inches of snow to the West Central Mountains and between 4 and 9 inches of snow to the Boise Mountains.

Where it happened

Every event with a place to put it; 2 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

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 2

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 strong Pacific storm brought between 4 and 12 inches of snow to the West Central Mountains and between 4 and 9 inches of snow to the Boise Mountains.

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 Dec 4, 9:35 PM MST, 25 minutes earlier.

Area forecast discussion, Dec 4, 9:35 PM MST, 25 minutes before

SOUTHWEST IDAHO/SOUTHEAST OREGON AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE IDAHO
935 PM MST TUE DEC 04 2001

...ZONE FORECASTS UPDATED TO REMOVE SNOW ADVISORY FROM SOUTHERN
ZONES TONIGHT...UPPER LEVEL S/WV TROUGH ALONG WA COAST AT 03Z TO DIG
QUICKLY THROUGH PACIFIC NORTHWEST TONIGHT INTO SOUTHWEST ID EARLY
WED DUE TO STRONG 140+ KT NORTHWESTERLY JET CORE ON WEST SIDE OF
TROUGH. SNOW INTO SOUTHEAST ORE ZONES BY 02Z AND BEGINNING MYL AREA
AT 03Z. AMPLE JET /TROUGH DYNAMICS BUT RAPID PASSAGE OF SYSTEM
THROUGH CWFA WILL LIMIT SNOW ACCUMULATIONS TO NORTHERN ZONES TONIGHT
IN ADVISORY LEVELS BUT LESSER AMOUNTS SOUTHERN ZONES. HAVE ALREADY
REMOVED SOUTHERN ZONES FROM SNOW ADVISORY TONIGHT. SCATTERED SNOW
SHOWERS WED WHILE STRONGER TROUGH AROUND 160W AT 03Z RAPIDLY
APPROACHES NORTHWEST COAST FOR WED NIGHT/THU PASSAGE THROUGH CWFA.
THIS SYSTEM HAS TAPPED TROPICAL MOISTURE WEST OF HAWAII WITH
SATELLITE PRECIPITABLE WATER VALUES OVER 1 INCH ALONG 160W TO 50N.
WARM OVER-RUNNING PRECIPITATION SPREADS INTO CWFA LATE WED WITH SNOW
CHANGING TO RAIN LOWEST SOUTHWEST ID VALLEYS BUT REMAIN SNOW ABOVE
4K THROUGH THU. WINTER STORM WATCH LATE WED NIGHT/THU LOOKS GOOD AT
THIS TIME.  00Z ETA/NGM SLOWER AND WEAKER WITH THIS S/WV THAN
PREVIOUS MODELS WHILE AVN JUST A LITTLE WEAKER LOOKING. STILL SYSTEM
CROSSES CWFA WITH 120+ KT ZONAL JET FOR GOOD OROGRAPHIC LIFT THU. NO
CHANGES BEYOND THU AT THIS TIME.  PARKER

.BOI...SNOW ADVISORY FOR WEST CENTRAL/BOISE MOUNTAINS (ID ZNS
       11/13) AND BAKER CNTY (ORE ZN 62) TONIGHT AND EARLY WED.
       WINTER STORM WATCH FOR IDAHO ZONES 11 13 28 29 AND
       OREGON ZONES 61 62 63 FOR WED NIGHT AND EARLY THU.

The radar

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

Open the radar archive at this moment

Event by event

2 heavy snow. Local standard time, as filed.

Heavy Snow, West Central Mountains

When: December 4, 10:00 PM MST to December 5, 9:00 AM MST
Where: West Central Mountains forecast zone
Reported by: TRAINED SPOTTER
Coordinates: 44.543, -116.300 (the zone’s center; the record gives no point)

Heavy Snow, Boise Mountains

When: December 4, 10:00 PM MST to December 5, 9:00 AM MST
Where: Boise Mountains forecast zone
Reported by: TRAINED SPOTTER
Coordinates: 43.602, -115.335 (the zone’s center; the record gives no point)

What these are

Heavy Snow: Snowfall reaching the local warning threshold without the other hazards of a winter storm.

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

The same day elsewhere

Every storm in Idaho in 2001 Every state in 2001 This day in weather history Warnings in Idaho, December 2001

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: 5276212, 5276213.