A strong upper level low pressure system from the Gulf of Alaska moved through the region, pushing a strong jet stream and cold front into the northern Rockies. Moderate to heavy snow fell in portions of Glacier National Park, with total snow amounts ranging from six to 13 inches.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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 MSO wrote it up.
A strong upper level low pressure system from the Gulf of Alaska moved through the region, pushing a strong jet stream and cold front into the northern Rockies. Moderate to heavy snow fell in portions of Glacier National Park, with total snow amounts ranging from six to 13 inches.
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 Missoula, MT wrote its last area forecast discussion before the first event at May 3, 2:59 AM MST, 1 minute earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
359 AM MDT MON MAY 3 2010
...DAMAGING WINDS ACROSS THE INTERMOUNTAIN REGION TODAY INTO TONIGHT...
.DISCUSSION...A VERY WINDY DAY ON TAP AS A VIGOROUS COLD FRONT
AND ASSOCIATED STRONG UPPER LEVEL JET INFLUENCE THE INTERMOUNTAIN
REGION. CURRENTLY THE SURFACE FRONT AND UPPER JET ARE MOVING INTO
THE NORTHWEST WASHINGTON COAST. AHEAD OF THE FRONT...WARM FRONT
PROCESSES ARE RESULTING IN WIDESPREAD RAIN. CURRENTLY RAIN IS
ENVELOPING EASTERN WASHINGTON AND OREGON AND THE IDAHO PANHANDLE
AND INCREASING IN COVERAGE. MUCH OF NORTH CENTRAL IDAHO AND
WESTERN MONTANA SHOULD SEE RAIN BY DAYBREAK.
THE WINDS WILL BE INTERESTING TODAY. EXPECT THERE WILL BE TWO
DISTINCT OCCURRENCES. THE FIRST WAVE WILL ACCOMPANY THE COLD FRONT
WITH A BRIEF PERIOD OF STRONG GUSTS AND A BURST OF PRECIPITATION.
HOWEVER DO NOT THINK THESE WILL BE THE STRONGEST/MOST DAMAGING
WINDS. INSTEAD...BELIEVE THE DRYING AND SUBSEQUENT CONVECTION
THAT DEVELOPS BEHIND THE FRONT WILL ALLOW THE VERY STRONG WINDS AT
RIDGETOP LEVEL (GREATER THAN 50 KTS AT 8000 FEET) TO BE MIXED TO
THE SURFACE. GIVEN THE NATURE OF CONVECTION...CANNOT EXACTLY PIN
POINT WHERE/WHEN THE STRONGEST WINDS WILL DEVELOP. HOWEVER...THESE
STRONG RIDGETOP WINDS ARE OVER THE ENTIRE INTERMOUNTAIN REGION AS
WELL AS THE POTENTIAL FOR CONVECTION THIS AFTERNOON. THEREFORE
HAVE BLANKETED NORTH CENTRAL IDAHO AND WESTERN MONTANA WITH HIGH
WIND WARNINGS FOR LATE THIS MORNING THROUGH THIS EVENING. THE
EXCEPTION IS THE LOWER HELLS CANYON AND CAMAS PRAIRIE REGIONS AS
THEY WILL SEE THEIR STRONGEST WINDS AHEAD OF THE FRONT FROM A MORE
SOUTHERLY DIRECTION. THEREFORE HAVE MAINTAINED A WIND ADVISORY
THERE. PLEASE SEE WWW.WEATHER.GOV/MISSOULA FOR SPECIFIC DETAILS
ABOUT THE WIND HIGHLIGHTS.
GUSTY WINDS WILL LINGER INTO THIS EVENING ACROSS NORTH CENTRAL
IDAHO AND WESTERN MONTANA...AND UNTIL TUESDAY MORNING ALONG THE
CONTINENTAL DIVIDE. ANOTHER BREEZY DAY IS EXPECTED TUESDAY...BUT
NOT TO THE DEGREE TODAY WILL BE.
MUCH COOLER AIR BEHIND THE FRONT WILL KEEP TEMPERATURES SOME 20
DEGREES BELOW NORMAL FOR TUESDAYS HIGHS. MANY LOCATIONS WILL SEE A
RAIN/SNOW MIX IN THE VALLEYS WITH ALL SNOW EXPECTED ALONG THE
DIVIDE TONIGHT AND TUESDAY. SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED ALONG THE DIVIDE AND COMBINED WITH BREEZY WINDS...MAY
RESULT IN SOME TRAVEL IMPACTS.
TUESDAY NIGHT THROUGH THURSDAY...SHOWERS ARE EXPECTED TO LINGER
ACROSS THE REGION TUESDAY NIGHT AS THE NORTHERN ROCKIES FALLS
BETWEEN TWO SYSTEMS. MEANWHILE A CLOSED LOW PRESSURE SYSTEM WILL
BEGIN TO PUSH INTO THE PACIFIC NORTHWEST OVERNIGHT TUESDAY. THE
CURRENT STORM TRACK TAKES THIS SYSTEM INTO SOUTHERN IDAHO
WEDNESDAY AND CONTINUES TO DIG THE SYSTEM TO THE SOUTH WEDNESDAY
NIGHT. ON WEDNESDAY AN ROBUST AREA OF DEFORMATION AND A STRONG JET
STREAK WILL HELP TO ENHANCE LIFT AND PRECIPITATION ACROSS THE
REGION...PARTICULARLY NORTH CENTRAL IDAHO AND SOUTHWEST MONTANA.
AS THE LOW PUSHES TO THE EAST THURSDAY MORNING...WRAPAROUND
MOISTURE FROM THE MID-LEVEL CIRCULATION SHOULD ENHANCE UPSLOPE
PRECIPITATION ALONG THE CONTINENTAL DIVIDE IN SOUTHWEST MONTANA
AND LEMHI COUNTY IDAHO...CREATING AREAS OF HEAVIER PRECIPITATION
AND DRIVING SNOW LEVELS DOWN. MOUNTAIN PASSES AND HIGHER VALLEYS
ARE EXPECTED TO EXPERIENCE LIGHT TO MODERATE SNOW ACCUMULATIONS
THUS CREATING POTENTIAL IMPACTS TO TRAVEL. GIVEN THE CURRENT
HIGHLIGHTS FOR WIND AND THE VARIABLE NATURE OF CLOSED LOW SYSTEMS...
WILL ISSUE A WEATHER STORY HIGHLIGHTING POTENTIAL IMPACTS EXPECTED
WEDNESDAY THROUGH THURSDAY.
FRIDAY THROUGH THE WEEKEND REMAINS UNSETTLED UNDER NORTHWEST FLOW
ALOFT WITH VARIOUS SHORTWAVE FEATURES MOVING OVER THE REGION.
&&
.AVIATION...SOUTHWEST WINDS WILL INCREASE THIS MORNING AS A
VIGOROUS COLD FRONT AND ASSOCIATED UPPER LEVEL JET PASS THROUGH
THE REGION. WINDS WILL COME IN TWO WAVES. THE FIRST WILL BE
ASSOCIATED WITH THE FRONTAL PASSAGE. THE SECOND WAVE WILL COME
POST FRONTAL ASSOCIATED WITH CONVECTION THAT DEVELOPS. SOUNDINGS
INDICATE SHOWERS COULD EASILY MIX GUSTS IN EXCESS OF 50 MPH TO THE
SURFACE THIS AFTERNOON AND EVENING. ALL AIRFIELDS WILL BE IMPACTED
BY STRONG WINDS. AT THIS TIME THE FRONT LOOKS TO PASS THROUGH
NORTHWEST AND NORTH CENTRAL MONTANA BETWEEN 15-18Z AND SOUTHWEST MONTANA
AND LEMHI COUNTY BETWEEN 18Z-21Z. PRECIPITATION WILL BE WIDESPREAD
ACROSS THE INTERMOUNTAIN REGION TODAY. STRATIFORM THIS
MORNING...BECOMING CONVECTIVE THIS AFTERNOON AND EVENING. TERRAIN
OBSCURATIONS SHOULD BE EXPECTED THROUGH THE DAY AND TONIGHT.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...HIGH WIND WARNING FROM NOON TODAY TO 4 AM MDT TUESDAY
BUTTE/BLACKFOOT REGION...POTOMAC/SEELEY LAKE REGION.
HIGH WIND WARNING FROM NOON TODAY TO 4 AM MDT TUESDAY
BITTERROOT/SAPPHIRE MOUNTAINS.
HIGH WIND WARNING FROM NOON TODAY TO 10 PM MDT THIS EVENING
MISSOULA/BITTERROOT VALLEYS.
HIGH WIND WARNING FROM NOON TODAY TO 9 PM MDT THIS EVENING
FLATHEAD/MISSION VALLEYS.
HIGH WIND WARNING FROM 9 AM THIS MORNING TO 4 AM MDT TUESDAY
WEST GLACIER REGION.
HIGH WIND WARNING FROM 10 AM THIS MORNING TO 9 PM MDT TUESDAY
KOOTENAI/CABINET REGION.
HIGH WIND WARNING FROM 10 AM THIS MORNING TO 9 PM MDT TUESDAY
LOWER CLARK FORK REGION.
ID...HIGH WIND WARNING FROM 2 PM THIS AFTERNOON TO 4 AM MDT TUESDAY
EASTERN LEMHI COUNTY...WESTERN LEMHI COUNTY.
HIGH WIND WARNING FROM 11 AM THIS MORNING TO 3 AM PDT TUESDAY
NORTHERN CLEARWATER MOUNTAINS...SOUTHERN CLEARWATER
MOUNTAINS.
WIND ADVISORY UNTIL 5 PM PDT THIS AFTERNOON LOWER HELLS
CANYON/SALMON RIVER REGION...OROFINO/GRANGEVILLE REGION.
&&
SHORT TERM...MEAD
LONG TERM....DE ROSA
AVIATION...MEADThe national radar mosaic for the moment the first event began.
1 winter storm. Local standard time, as filed.
A spotter in Swan Lake reported seven inches of new snow. A spotter in Essex reported six inches of snow in 12 hours, 13 inches of snow total.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2010Every state in 2010This day in weather historyWarnings in Montana, May 2010
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: 230464.