Blizzard and Heavy Snow in Montana, March 18 to 21, 2002

Name: Blizzard and Heavy Snow in Montana, March 18 to 21, 2002
Start: 2002-03-18T13:22
End: 2002-03-21T00:00
Location: Montana

March 18 to 21, 2002 · NWS MSO · 9 events in 7 counties and zones

Where it happened

Every event with a place to put it; 9 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: 9

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.

A major winter like spring storm developed over western Montana as Pacific moisture and an arctic front combined to dump record breaking heavy snow over the region for three days. Local blizzard conditions developed over portions of western Montana on the third day, as the arctic front pushed over the Continental Divide and southward into the Bitterroot Valley. North winds increased to between 30 and 40 mph just behind the arctic front, with most roads declared emergency travel only by the DOT. Many northwest Montana schools were closed down. Average snowfall in the valleys ranged from 6 to 12 inches, with one to two feet of new snow in the mountains. The West Glacier and Blackfoot Regions received the most snow with 29 to 39 inches reported. Kalispell Airport broke a three day snowfall record with 20 inches and a record low temperature of 10 degrees on March 20. In the Mission Valley, snow drifts of 3 to 4 feet were reported.

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 18, 9:07 AM MST, 4 hours 15 minutes earlier.

Area forecast discussion, Mar 18, 9:07 AM MST, 4 hours 15 minutes before

WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
830 AM MST MON MAR 18 2002

.SHORT TERM...WILL UPDATE ZFP/SFP THIS MORNING. A SHORT-WAVE TROUGH
AND SURFACE LOW OVER THE NORTHWEST PORTION OF THE CWA PROVIDING
DECENT LIFT IN A AREA WHERE LAPSE RATES ARE STILL FAVORABLE FOR
SCATTERED SNOW SHOWERS. PREVIOUS MODELS RUNNING A LITTLE SLOW WITH
THE TIMING OF A VIGOROUS SHORT-WAVE TROUGH CURRENTLY APPROACHING
WASHINGTON. FORECAST NEEDS TO BE SPED UP AND WILL INCREASE CLOUDS AND
POPS ACROSS THE NORTH BASED ON SATELLITE AND RADAR. NEW MESOETA STILL
DOES NOT SEEM KEEP UP WITH THE OVERALL SPEED OF SYSTEM. DYNAMICS
COMING TOGETHER WITH GOOD LIFT FROM ONE JET CORE EXITING AND ANOTHER
PUNCHING INTO THE PACIFIC NORTHWEST. IN ADDITION...A WEAKNESS IN THE
SURFACE PRESSURE FIELD LIES ACROSS THE NORTHERN PORTION OF THE CWA
PROVIDING WEAK CONVERGENCE. BETTER MOISTURE BECOMING AVAILABLE BY
AFTERNOON AND WILL WILL INCREASE THE POPS TO LIKELY IN THE EXTREME
NORTHWEST CORNER MTZ001-004 BY LATE AFTERNOON...AS WELL INCREASE
POPS TO CHANCE CATEGORY IN THE IDZ005-007-MTZ002-003.

WILL NOT CHANGE WSW FROM WATCH YET...AND WILL WAIT UNTIL THIS
AFTERNOON WITH THE BENEFIT OF UPDATED MODELS.
MSJ

.MSO...WINTER STORM WATCH TONIGHT THROUGH WEDNESDAY IDZ005>008
       AND MTZ001>006-043...

...7-DAY SPOT TEMPS AND POPS...
LIB CSS /031 020/031 019/027 3966887
     EEOO 018/034 014/038 020/040 022/040 024/ 39520035553
FCA ESS /027 018/029 016/025 3936788
     EEOO 016/032 012/034 020/040 022/040 024/ 39520035553
POL ESS /029 021/031 020/029 3936788
     EEOO 019/034 018/039 024/042 023/039 026/ 39520035553
MSO ESS /030 022/035 025/034 3926776
     EEOO 018/034 016/037 022/042 022/042 024/ 39520035454
HMM ESS /033 024/038 027/035 3916666
     EECC 020/036 018/040 023/044 023/044 025/ 39420024444
BTM ECS /027 014/034 019/030 3913566
     EBCC 010/033 007/036 015/040 019/040 021/ 39431014333
ORO COR /043 031/046 035/044 3937775
     EERR 033/046 034/049 036/053 036/052 038/ 39520135554
GRV COO /037 028/040 030/039 3917775
     EERO 029/041 028/045 033/050 033/048 035/ 39520135544
SMN CCO /034 022/041 028/039 3914553
     EBCE 023/040 020/043 023/045 027/043 029/ 39320024434

The radar

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

Open the radar archive at this moment

Event by event

5 heavy snow, 4 blizzard. Local standard time, as filed.

Heavy Snow, Kootenai/Cabinet Region

When: March 18, 1:22 PM MST to March 20, 4:00 PM MST
Where: Kootenai/Cabinet Region forecast zone
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 48.171, -114.863 (the zone’s center; the record gives no point)

Heavy Snow, West Glacier Region

When: March 18, 1:22 PM MST to March 20, 4:00 PM MST
Where: West Glacier Region forecast zone
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 47.971, -114.069 (the zone’s center; the record gives no point)

Heavy Snow, Lower Clark Fork Region

When: March 18, 1:22 PM MST to March 20, 4:00 PM MST
Where: Lower Clark Fork Region forecast zone
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 47.286, -114.685 (the zone’s center; the record gives no point)

Heavy Snow, Bitterroot / Sapphire Mountains

When: March 19, 4:30 AM MST to March 20, 4:30 AM MST
Where: Bitterroot / Sapphire Mountains forecast zone
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 46.508, -113.828 (the zone’s center; the record gives no point)

Blizzard, Kootenai/Cabinet Region

When: March 20, 4:30 AM MST to March 21, 12:00 AM MST
Where: Kootenai/Cabinet Region forecast zone
Reported by: TRAINED SPOTTER
Coordinates: 48.171, -114.863 (the zone’s center; the record gives no point)

Blizzard, West Glacier Region

When: March 20, 4:30 AM MST to March 21, 12:00 AM MST
Where: West Glacier Region forecast zone
Reported by: TRAINED SPOTTER
Coordinates: 47.971, -114.069 (the zone’s center; the record gives no point)

Blizzard, Flathead/Mission Valleys

When: March 20, 4:30 AM MST to March 21, 12:00 AM MST
Where: Flathead/Mission Valleys forecast zone
Reported by: TRAINED SPOTTER
Coordinates: 47.872, -114.424 (the zone’s center; the record gives no point)

Heavy Snow, Missoula / Bitterroot Valleys

When: March 20, 4:00 PM MST to March 21, 12:00 AM MST
Where: Missoula / Bitterroot Valleys forecast zone
Reported by: TRAINED SPOTTER
Coordinates: 46.560, -114.023 (the zone’s center; the record gives no point)

Blizzard, Blackfoot Region

When: March 20, 4:00 PM MST to March 21, 12:00 AM MST
Where: Blackfoot Region forecast zone
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 46.986, -113.597 (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.
Blizzard: Sustained winds or frequent gusts of 35 mph or more with falling or blowing snow that cuts visibility below a quarter mile for three hours or longer.

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

The same day elsewhere

Every storm in Montana in 2002 Every state in 2002 This day in weather history Warnings in Montana, March 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: 5281846, 5281847, 5281848, 5281849, 5281850, 5281851, 5281852, 5281853, 5281854.