Winter Storm in Montana, April 18 to 19, 2011

Name: Winter Storm in Montana, April 18 to 19, 2011
Start: 2011-04-18T17:00
End: 2011-04-19T17:00
Location: Montana

April 18 to 19, 2011 · NWS TFX · 2 events in 2 counties and zones

A spring storm brought heavy snow to elevations above 6000 feet in Fegus and Gallatin counties. Snow amounts up to a foot were reported.

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 TFX wrote it up.

A spring storm brought heavy snow to elevations above 6000 feet in Fegus and Gallatin counties. Snow amounts up to a foot 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 Great Falls, MT wrote its last area forecast discussion before the first event at Apr 18, 4:45 PM MST, 15 minutes earlier.

Area forecast discussion, Apr 18, 4:45 PM MST, 15 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
545 PM MDT MON APR 18 2011

.DISCUSSION...

TONIGHT THROUGH TUESDAY NIGHT...WIDESPREAD SNOW SHOWERS HAVE
DEVELOPED THIS AFTERNOON DUE TO DAYTIME HEATING. AM NOT EXPECTING
SIGNIFICANT ACCUMULATION FROM THESE SHOWERS THIS EVENING.
HOWEVER...A SHORTWAVE TROUGH WILL THEN MOVE INTO THE TFX CWA FROM
THE PACIFIC NORTHWEST LATER THIS EVENING...BRINGING INCREASED
MOISTURE AND LIFT TO MOST OF THE AREA. WITH A SURFACE LOW PRESSURE
AREA EXPECTED TO MOVE ACROSS SOUTHWESTERN MONTANA OVERNIGHT...THE
RESULTING NORTHERLY UPSLOPE WINDS WILL BRING ENHANCED SNOWFALL TO
THE FAVORED UPSLOPE AREAS ACROSS CENTRAL MONTANA. HAVE THEREFORE
UPGRADED THE WINTER WEATHER ADVISORY IN CASCADE...JUDITH
BASIN...AND FERGUS COUNTIES TO A WINTER STORM WARNING FOR ABOVE
5000 FEET. MODELS SPREAD THE PRECIPITATION FARTHER NORTH AS
WELL...SO HAVE ISSUED WINTER WEATHER ADVISORIES FROM THE ROCKY
MOUNTAIN FRONT THROUGH EASTERN PORTIONS OF GLACIER...PONDERA...AND
TETON COUNTIES...INTO CHOUTEAU COUNTY. AM NOT EXPECTING THE
HIGHEST PRECIPITATION AMOUNTS TO GET INTO SOUTHERN GALLATIN
COUNTY...SO HAVE ONLY UPGRADED THE ADVISORY THERE TO A WARNING
ABOVE 6000 FEET (TO MATCH UP WITH MEAGHER COUNTY) FOR NORTHERN
GALLATIN COUNTY (MAINLY FOR THE BRIDGER MOUNTAINS).
OVERALL...ADVISORY AREAS SHOULD RECEIVE 2 TO 5 INCHES OF SNOW WITH
6 TO 10 INCHES IN THE MOUNTAINS. WARNING AREAS COULD RECEIVE 9 TO
14 INCHES OF SNOW. SNOW WILL BEGIN TO DECREASE TUESDAY AFTERNOON.
AS THE SYSTEM MOVES EAST TUESDAY NIGHT AND THE UPPER RIDGE
DEVELOPS EXPECT SNOW TO DIMINISH AND MOSTLY END OVER THE ENTIRE
FORECAST AREA. THIS SYSTEM WILL ALSO KEEP DAYTIME TEMPERATURES
BELOW NORMAL...WHILE OVERNIGHT LOWS WILL REMAIN NEAR TO SLIGHTLY
ABOVE NORMAL. COULSTON/BLANK

WEDNESDAY THROUGH MONDAY...EXPECT THE PROLONGED COOL AND UNSETTLED
SPRING/LATE WINTER WEATHER PATTERN TO CONTINUE OVER THE REGION.
FORECAST MODELS WHERE HINTING AT SOME WARMER AND DRIER AIR MOVING
INTO THE REGION BY NEXT WEEKEND...BUT THAT HAS CHANGED BACK TO
COOLER/WET WEATHER BY SUNDAY. THINGS SHOULD DRY OUT FOR A FEW HOURS
ON WEDNESDAY...AS THE REGION WILL BE IN-BETWEEN STORM SYSTEMS.
HOWEVER...BY THURSDAY AFTERNOON EXPECT INCREASING CHANCES FOR
PRECIPITATION...ESPECIALLY OVER CENTRAL AND SOUTHWEST MONTANA. THE
PRECIPITATION CONTINUES INTO FRIDAY MORNING...BEFORE DIMINISHING A
BIT ON SATURDAY. BY SUNDAY AFTERNOON...ANOTHER STORM SYSTEM WILL
AFFECT THE WESTERN PORTIONS OF THE REGION...BRINGING WITH IT ANOTHER
CHANCE FOR RAIN/SNOW. THIS SYSTEM FOR SUNDAY/MONDAY SHOULD HAVE A
BIT WARMER AIR WITH IT...SO MAINLY RAIN IS EXPECTED AT LOWER
ELEVATIONS DURING THE DAY...WITH A MIX OF RAIN/SNOW AT NIGHT. IN THE
MOUNTAINS...MAINLY SNOW IS EXPECTED. THERE WILL BE A CHANCE FOR
ACCUMULATING SNOWS THURSDAY THROUGH FRIDAY AND AGAIN SUNDAY THROUGH
MONDAY...ESPECIALLY IN THE MOUNTAINS...AND THIS WILL BE WATCHED
CLOSELY OVER THE NEXT FEW DAYS. IN TERMS OF TEMPERATURES...EXPECT
THE BELOW NORMAL TEMPERATURES TO CONTINUE...WITH WARMEST DAY LOOKING
TO BE NEXT SUNDAY...AND EVEN ON THAT DAY...AFTERNOON TEMPERATURES
SHOULD STILL AVERAGE BETWEEN 5 AND 10 DEGREES BELOW NORMAL. BRUSDA

&&

.AVIATION...
UPDATED 2345Z.
WIDESPREAD LIGHT SNOW AND FOG WILL AFFECT NORTH CENTRAL MONTANA
THROUGH THE PERIOD AS A STORM SYSTEM MOVES THROUGH THE REGION.
COMBINATION OF FOG AND AREAS OF SNOW WILL BRING MVFR TO IFR
CONDITIONS TO MUCH OF THE REGION WITH MOUNTAIN OBSCURATIONS. SNOW
EXPECTED TO DECREASE WITH GRADUALLY IMPROVING CONDITIONS ACROSS THE
REGION AFTER 18Z TUESDAY.

&&

.HYDROLOGY...
BLAINE COUNTY OFFICIALS REPORT THIS AFTERNOON THAT STREAMS AND
CREEKS HAVE LOWERED AND ARE GENERALLY NOT POSING A PROBLEM
ANYMORE. THEREFORE...THE FLOOD ADVISORY FOR BLAINE COUNTY HAS BEEN
CANCELLED.  COULSTON

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  25  37  25  49 / 100  90  20  10
CTB  21  36  23  45 / 100  80  20  10
HLN  28  41  26  52 /  70  60  20  10
BZN  26  38  22  53 / 100  90  30  10
WEY  20  29   9  38 /  90  70  30  20
DLN  24  37  21  49 /  70  30  20  10
HVR  25  41  26  52 /  60  40  20  10
LWT  24  31  16  43 / 100 100  30  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM MDT TUESDAY CHOUTEAU...
EASTERN GLACIER...EASTERN PONDERA...EASTERN TETON...NORTHERN
ROCKY MOUNTAIN FRONT...SOUTHERN ROCKY MOUNTAIN FRONT.

WINTER WEATHER ADVISORY UNTIL 6 PM MDT TUESDAY FOR ELEVATIONS
BELOW 6000 FEET FOR GALLATIN...MEAGHER.

WINTER STORM WARNING UNTIL 6 PM MDT TUESDAY FOR ELEVATIONS ABOVE
6000 FEET FOR GALLATIN...MEAGHER.

WINTER WEATHER ADVISORY UNTIL 6 PM MDT TUESDAY FOR ELEVATIONS
BELOW 5000 FEET FOR CASCADE...FERGUS...JUDITH BASIN.

WINTER STORM WARNING UNTIL 6 PM MDT TUESDAY FOR ELEVATIONS ABOVE
5000 FEET FOR CASCADE...FERGUS...JUDITH BASIN.

&&

SHORT TERM...COULSTON/BLANK
LONG TERM...BRUSDA/WARANAUSKAS
AVIATION...LANGLIEB

WEATHER.GOV/GREATFALLS

Hazardous weather outlook, Apr 18, 2:17 PM MST, 2 hours 43 minutes before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE GREAT FALLS MT
317 PM MDT MON APR 18 2011

MTZ012-050-051-054-055-191100-
CASCADE-JUDITH BASIN-FERGUS-MEAGHER-GALLATIN-
317 PM MDT MON APR 18 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA
AND SOUTHWEST MONTANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

A WINTER STORM WARNING HAS BEEN ISSUED FOR THE MOUNTAINS AND A
WINTER WEATHER ADVISORY IS IN EFFECT FOR LOWER ELEVATIONS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE WINTER WEATHER HIGHLIGHTS REMAIN IN EFFECT THROUGH TUESDAY
AFTERNOON.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS REQUIRED OVERNIGHT AND THROUGH THE DAY ON
TUESDAY. REPORTS OF SNOWFALL...ICE ACCUMULATION OR SIGNIFICANT
RESTRICTIONS TO VISIBILITY WOULD BE GREATLY APPRECIATED.

MTZ009-010-013-046-048-049-191100-
NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-CHOUTEAU-
EASTERN PONDERA-SOUTHERN ROCKY MOUNTAIN FRONT-EASTERN TETON-
317 PM MDT MON APR 18 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
MONTANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

A WINTER WEATHER ADVISORY IS IN EFFECT OVERNIGHT.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE WINTER WEATHER ADVISORY REMAINS IN EFFECT THROUGH TUESDAY
AFTERNOON.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS REQUIRED OVERNIGHT AND THROUGH THE DAY ON
TUESDAY. REPORTS OF SNOWFALL...ICE ACCUMULATION OR SIGNIFICANT
RESTRICTIONS TO VISIBILITY WOULD BE GREATLY APPRECIATED.

MTZ008-011-014-015-044-045-047-052-053-191100-
BEAVERHEAD-HILL-CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON-
TOOLE-LIBERTY-BLAINE-JEFFERSON-BROADWATER-
317 PM MDT MON APR 18 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
MONTANA AND SOUTHWEST MONTANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

In the hours before

Local storm report, Apr 18, 2:09 PM MST, 2 hours 51 minutes before

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE GREAT FALLS MT
309 PM MDT MON APR 18 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1000 PM     SNOW             GRASS RANGE             47.03N 108.80W
04/17/2011  M1.0 INCH        FERGUS             MT   CO-OP OBSERVER

            ONE INCH OF SNOW SINCE 8 PM.

0200 AM     SNOW             24 W BYNUM              47.92N 112.82W
04/18/2011  E9.0 INCH        TETON              MT   MESONET

            ESTIMATED 9 INCHES OF NEW SNOW IN THE PAST 24 HOURS AT
            THE MOUNT LOCKHART SNOTEL. ELEVATION IS 6400 FEET.

0500 AM     HEAVY SNOW       11 SSW EAST GLACIER PAR 48.30N 113.33W
04/18/2011  E11.0 INCH       GLACIER            MT   MESONET

            ESTIMATED 11 INCHES OF NEW SNOW IN THE PAST 24 HOURS AT
            THE PIKE CREEK SNOTEL. ELEVATION IS 5930 FEET.

0500 AM     SNOW             14 SW HEART BUTTE       48.13N 113.02W
04/18/2011  E7.0 INCH        PONDERA            MT   MESONET

            ESTIMATED 7 INCHES OF NEW SNOW IN THE PAST 24 HOURS AT
            THE BADGER PASS SNOTEL. ELEVATION IS 6900 FEET.

0500 AM     SNOW             23 W BYNUM              47.92N 112.79W
04/18/2011  E7.0 INCH        TETON              MT   MESONET

            ESTIMATED 7 INCHES OF NEW SNOW IN THE PAST 15 HOURS AT
            THE WALDRON SNOTEL. ELEVATION IS 5600 FEET.

&&

EVENT NUMBER TFX1100712 TFX1100715 TFX1100713 TFX1100714 TFX1100716

LOSS

Event by event

2 winter storm. Local standard time, as filed.

Winter Storm, Fergus

When: April 18, 5:00 PM MST to April 19, 5:00 PM MST
Where: Fergus forecast zone
Reported by: Mesonet

Twelve inches of snow fell at Garneill 12ENE (the Crystal Lake SNOTEL site - elevation 6050 feet).

Winter Storm, Gallatin

When: April 18, 5:00 PM MST to April 19, 9:33 AM MST
Where: Gallatin forecast zone
Reported by: Mesonet

Eight inches of snow fell at Gallatin Gateway 13ESE (the Lick Creek SNOTEL site - elevation 6860 feet).

What these are

Winter Storm: A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.

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

The same day elsewhere

Every storm in Montana in 2011 Every state in 2011 This day in weather history Warnings in Montana, April 2011

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: 299739, 299742.