An upper level low pressure center over eastern Washington brought locally heavy snow to the higher elevations of the central Idaho panhandle. Nine inches of snow fell along I-90 at Fourth of July Pass, and the Lost Lake SNOTEL estimated 7" of the late season snow.
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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.
The episode as NWS OTX wrote it up.
An upper level low pressure center over eastern Washington brought locally heavy snow to the higher elevations of the central Idaho panhandle. Nine inches of snow fell along I-90 at Fourth of July Pass, and the Lost Lake SNOTEL estimated 7" of the late season snow. Even the lower elevations of north Idaho received one inch or so of snow.
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 Spokane, WA wrote its last area forecast discussion before the first event at May 6, 8:00 AM PST, 4 hours earlier.
EASTERN WASHINGTON AND NORTH IDAHO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WASHINGTON 900 AM PDT MON MAY 06 2002 COLD UPPER LOW SPINNING OVER VANCOUVER ISLAND CONTINUES TO SAG VERY SLOWLY TO THE SOUTH. SHOWERS CONTINUE TO DEVELOP EVEN IN THE EARLY MORNING HOURS WHICH SHOWS PLENTY OF DYNAMIC LIFT IN PLACE FROM THE UPPER LOW. AVN AND ETA SHOW VERY IMPRESSIVE VALUES OF DIV-Q BY THIS AFTERNOON...CENTERED OVER THE NORTHERN MOUNTAINS. WHILE THE LAPSE RATES ARE JUST AS STEEP AS YESTERDAY...THE ACTUAL INSTABILITY IS A BIT LESS. THIS IS DUE TO DRIER AIR IN PLACE (DEW POINTS ARE DOWN 5- 10 DEGREES OVER SUNDAY) AND COOLER LOW LEVELS. STRONG DYNAMICS PLACE THE FOCUS OF ACTIVITY TODAY OVER THE NORTHERN ZONES SO WILL BEEF UP THE POPS THERE A BIT. THUNDERSTORMS ALSO LOOK TO BE A GOOD BET UP THERE SINCE EQUILIBRIUM LEVELS SHOULD HAVE NO PROBLEM REACHING THE -30C LEVEL THIS AFTERNOON. ELSEWHERE SHOWER AND THUNDER ACTIVITY SHOULD BE MORE IN THE SCATTERED CATEGORY WITH ONLY ISOLATED ACTIVITY IN THE BASIN AND LOWER ELEVATIONS OF THE EAST SLOPES. RJ ...THE INFORMATION IN THIS PRODUCT CONCERNING WARNINGS AND FORECASTS IS VALID ONLY AT THE TIME OF ISSUANCE. THE LATEST WARNING AND FORECAST INFORMATION WILL BE FOUND IN THE APPROPRIATE PRODUCTS... GEG 048/033/051/034/055 54321 COE 047/032/049/033/056 54321 PUW 050/033/051/034/054 54321 LWS 055/038/057/039/061 42421 CQV 051/031/053/032/060 85321 SPT 047/031/049/031/055 85421 WWP 043/031/044/032/049 76531 EAT 055/034/056/035/060 22210 MWH 056/035/057/036/062 22210 .OTX...NONE.
The national radar mosaic for the moment the first event began.
1 heavy snow. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2002Every state in 2002This day in weather historyWarnings in Idaho, May 2002
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: 5299484.