Avalanche in Montana, March 12 to 13, 2003

Name: Avalanche in Montana, March 12 to 13, 2003
Start: 2003-03-12T06:55
End: 2003-03-13T06:55
Location: Montana

March 12 to 13, 2003 · NWS MSO · 1 event in 1 county or zone

Where it happened

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.

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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: 1

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 MSO wrote it up.

Heavy snow and cold temperatures from the week before, followed by temperatures in the 50s and gusty southwest winds lead to a large avalanche along Highway 2 between Essex and Marias Pass. The main slide occurred north of Silver Stair Falls snapping a highway guardrail and blocking both lanes of traffic. An automobile reportedly ran into the snow slide, but no injuries or property damage were reported. The Montana DOT closed the highway for two days due to the high potential for additional avalanches.

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 Missoula, MT wrote its last area forecast discussion before the first event at Mar 12, 2:51 AM MST, 4 hours 4 minutes earlier.

Area forecast discussion, Mar 12, 2:51 AM MST, 4 hours 4 minutes before

WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
251 AM MST WED MAR 12 2003

.SHORT TERM...LATEST MODELS ARE IN GOOD AGREEMENT WITH THE OVERALL
PATTERN THROUGH THURSDAY. A DEEP COLD TROUGH WILL DEVELOP IN THE
EASTERN PACIFIC RESULTING IN A PATTERN CHANGE OVER OUR AREA WITH A
FLAT BROAD RIDGE DEVELOPING ACROSS THE WEST LATER TODAY AND TONIGHT.
AT PRESENT MOIST WNW FLOW CONTINUES. A SHORTWAVE IN THIS FLOW OVER
EASTERN WA IS PRODUCING A LARGE AREA OF PRECIP MAINLY ACROSS THE
SOUTHERN HALF OF THE CWA. STRONG WESTERLY FLOW IS RESULTING IN
DOWNSLOPING IN THE VALLEYS. A DECREASE IN PRECIP IS EXPECTED THIS
MORNING AS THE SHORTWAVE MOVES EAST OF THE AREA. CURRENT WINTER STORM
WARNING WILL BE CANCELED AS THE BEST PRECIP IS SOUTH OF THE WARNING
AREA...AND SNOW LEVELS APPEAR HIGHER THEN FORECAST. WILL CONTINUE THE
FLOOD WATCH FOR SMALL STREAMS IN IDAHO AND CLEARWATER COUNTIES OF
IDAHO FOR TODAY AS WARM TEMPS AND ADDITIONAL RAINFALL MAY STILL LEAD
TO FLOODING PROBLEMS.

THE UPPER FLOW WILL BACK AS THE RIDGE DEVELOPS OVER THE AREA LATER
TODAY. A MID LEVEL WARM FRONT WILL DEVELOP LATER THIS AFTERNOON IN
THE INCREASING SOUTHWESTERLY FLOW ALOFT RESULTING IN ANOTHER INCREASE
IN PRECIP PRIMARILY FOR THE NORTHERN CLEARWATERS...EXTREME NORTHWEST
MONTANA AND POSSIBLY THE WEST GLACIER REGION THROUGH TONIGHT. THE
REMAINDER OF THE FORECAST AREA SHOULD SEE LOW POPS IN THIS
DOWNSLOPING FLOW. THIS UPPER FLOW WILL CONTINUE TO INCREASE AND BACK
ON THURSDAY AS THE UPPER RIDGE TRANSITIONS TO THE CENTRAL US. TIMING
OF WEAK SHORTWAVES IN THIS FLOW WILL BE TRICKY...BUT ANY SIGNIFICANT
PRECIP SHOULD STILL BE CONFINED MAINLY TO EXTREME NORTHWEST AND THE
NORTHERN CLEARWATERS. TEMPS CONTINUE TO WARM WITH THE HIGHEST
READINGS SINCE LAST FALL. A STRONGER SHORTWAVE IS PROGGED TO MOVE
ACROSS THE REGION ON THURSDAY NIGHT ACCORDING THE 00Z AND 06Z ETA AND
FRIDAY ACCORDING TO THE GFS. WILL TREND TOWARDS A COMPROMISE AT
THIS TIME. MODELS DO BRING A BURST OF PRECIP ACROSS THE REGION AS THE
ASSOCIATED COLD FRONT SWEEPS THROUGH THE AREA FROM WEST TO EAST. THE
FRONT WILL BRING SOME MINOR COOLING TO THE REGION FRIDAY. FOLLOWED BY
WARM AIR ADVECTION LATER IN THE DAY IN ADVANCE OF THE NEXT WEAK
SHORTWAVE. PETRESCU

.LONG TERM...NEW GFS SOLUTION HAS SIGNIFICANTLY CHANGED TIMING OF
MAIN FRONTAL SYSTEM PASSAGE.  SPECIFICALLY...NEW GFS HAS COME
AROUND TO YESTERDAYS ECMWF SOLUTION AND SHOWS FRONT COMING THROUGH
MISSOULA AREA ABOUT MIDNIGHT ON SATURDAY VERSUS PREVIOUS SLOWER
MONDAY FRONTAL PASSAGE.  THEREFORE...HAVE ADJUSTED GRIDS TO SHOW
ENHANCED PRECIPITATION OCCURRING SATURDAY AFTERNOON THROUGH SUNDAY
MORNING. WITH THESE CHANGES THE EXTENDED LOOKS LIKE THIS...
SOUTHWESTERLY FLOW ALOFT SATURDAY THROUGH TUESDAY WITH PACIFIC
FRONTAL PASSAGE OCCURRING LATE SATURDAY AND EARLY SUNDAY.  SINCE THIS
IS PACIFIC VERSUS ARCTIC AIR THAT WE HAVE BEEN DEALING WITH...
PRECIPITATION WILL BE MORE SEASONAL WITH MOSTLY RAIN IN VALLEYS AND
SNOW IN HIGHER MOUNTAINS. TEMPERATURES SHOULD FALL SEVERAL DEGREES
MOST LOCATIONS ON MONDAY AND TUESDAY AS COOLER AIR MOVES IN. MWJ

.MSO...FLOOD WATCH TODAY FOR SMALL STREAMS IN IDAHO AND
       CLEARWATER COUNTIES IN NORTH CENTRAL IDAHO...

...7-DAY SPOT TEMPS AND POPS...
LIB RWR /049 033/053 036/052 3866666
     RRBB 034/050 034/047 032/046 031/046 031/ 4165655432/
FCA EEN /045 031/051 032/050 3842254
     REBB 031/049 031/047 027/046 026/046 026/ 4125533432/
POL EEN /047 031/052 033/051 3842254
     REBB 033/051 033/049 029/048 028/048 028/ 4125534432/
MSO EEN /051 033/054 034/053 3832243
     REBB 033/050 033/048 030/047 029/047 029/ 4125534442/
HMM EBN /054 033/058 035/055 3832243
     REBB 034/054 034/052 028/051 027/051 027/ 4125534432/
BTM EBN /051 027/054 028/053 3831033
     EBBB 027/052 028/051 023/050 022/050 022/ 4124332532/
ORO REE /057 038/062 039/060 3863443
     EEBB 038/059 040/055 038/054 037/054 037/ 4133455432/
GRV REE /055 039/059 037/057 3863344
     RRBB 034/057 034/053 031/052 030/052 030/ 4134564332/
SMN EEN /053 029/056 029/053 3832034
     RBBB 028/052 031/049 027/048 026/048 026/ 4135454432/

Hazardous weather outlook, Mar 12, 6:00 AM MST, 55 minutes before

MTZ001>007-043-IDZ005>010-131300-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MISSOULA MT
600 AM MST WED MAR 12 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN MONTANA AND NORTH
CENTRAL IDAHO

.DAY ONE... TODAY

FLOOD WATCH CONTINUES FOR SMALL STEAMS OF CLEARWATER AND IDAHO
COUNTIES IN NORTH CENTRAL IDAHO TODAY DUE TO RECENT SNOW MELT...
REFER TO GTFFLSMSO FOR DETAILS. THE WARMING TREND WILL CONTINUE...
HOWEVER PRECIPITATION TOTALS WILL NOT BE AS HEAVY AS EXPECTED.

.DAYS TWO THROUGH SEVEN... THURSDAY THROUGH TUESDAY

THURSDAY AND FRIDAY...EXPECT CONTINUED WARMING TREND...RISING SNOW
LEVELS AND MOUNTAIN PRECIPITATION.  THE POTENTIAL WILL EXIST FOR
RISING STREAM FLOWS.

SATURDAY AND SUNDAY...A PACIFIC FRONT WILL PASS THROUGH THE AREA LATE
SATURDAY PRODUCING POTENTIAL FOR HEAVY SNOW IN WESTERN MOUNTAINS.

MONDAY AND TUESDAY...NO HAZARDOUS WEATHER IS EXPECTED

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

The radar

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

Open the radar archive at this moment

Event by event

1 avalanche. Local standard time, as filed.

Avalanche, West Glacier Region

When: March 12, 6:55 AM MST to March 13, 6:55 AM MST
Where: West Glacier Region forecast zone
Reported by: PARK/FOREST SERVICE
Coordinates: 47.971, -114.069 (the zone’s center; the record gives no point)

What these are

Avalanche: A mass of snow sliding down a mountainside that caused a death, an injury or damage.

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

The same day elsewhere

Every storm in Montana in 2003 Every state in 2003 This day in weather history Warnings in Montana, March 2003

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: 5346813.