237
WWUS45 KMSO 180726
WSWMSO
URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE MISSOULA MT
1226 AM MST THU DEC 18 2025
..ATMOSPHERIC RIVER TO BRING SIGNIFICANT MOUNTAIN SNOW
.A PLUME OF SUBTROPICAL MOISTURE ASSOCIATED WITH AN ATMOSPHERIC
RIVER WILL BRING SIGNIFICANT MOUNTAIN SNOW THURSDAY INTO FRIDAY.
SNOW LEVELS WILL RISE ABOVE 5,000 FEET THURSDAY NIGHT BEFORE QUICKLY
DROPPING FRIDAY MORNING AS STRONG COLD FRONT PASSES. THE HEAVIEST
SNOW ACCUMULATIONS WILL IMPACT HIGHER ELEVATIONS ABOVE 6,000 FEET,
ESPECIALLY ACROSS THE CLEARWATER AND BITTERROOT MOUNTAINS.
MTZ006-191915-
/O.UPG.KMSO.WW.Y.0049.251218T2000Z-251220T1800Z/
/O.NEW.KMSO.WS.W.0014.251219T0000Z-251220T0000Z/
BITTERROOT/SAPPHIRE MOUNTAINS-
1226 AM MST THU DEC 18 2025
...WINTER STORM WARNING IN EFFECT FROM 5 PM THURSDAY TO 5 PM MST
FRIDAY...
* WHAT...HEAVY SNOW EXPECTED. THERE IS A LIKELIHOOD OF MAJOR WINTER
WEATHER IMPACTS TO ISOLATED EXTREME WINTER STORM IMPACTS. TOTAL
SNOW ACCUMULATIONS BETWEEN 8 TO 14 INCHES FOR LOLO PASS AND 16 TO
24 INCHES FOR LOST TRAIL PASS. WINDS GUSTING BETWEEN 35 AND 45 MPH.
* WHERE...LOLO PASS AND HIGHWAY 93 SULA TO LOST TRAIL PASS.
* WHEN...FROM 5 PM THURSDAY TO 5 PM MST FRIDAY.
* IMPACTS...FOR MAJOR WINTER WEATHER IMPACTS, EXPECT CONSIDERABLE
DISRUPTIONS TO NORMAL ACTIVITIES. DANGEROUS OR IMPOSSIBLE
TRAVELING CONDITIONS. THE HAZARDOUS CONDITIONS COULD IMPACT THE
THURSDAY EVENING AND FRIDAY MORNING COMMUTES, ESPECIALLY OVER
HIGHER PASSES. GUSTY WINDS COULD BRING DOWN TREE BRANCHES, LEADING
TO POWER OUTAGES.
* ADDITIONAL DETAILS...SNOW WILL BRIEFLY CHANGE OVER TO RAIN AT LOLO
PASS THURSDAY NIGHT, BEFORE SWITCHING BACK TO SNOW EARLY FRIDAY
MORNING.
FOR LOST TRAIL PASS, SNOWFALL RATES WILL EXCEED ONE INCH PER HOUR
FOR SEVERAL HOURS THURSDAY NIGHT INTO FRIDAY MORNING.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
IF YOU MUST TRAVEL, KEEP AN EXTRA FLASHLIGHT, FOOD, AND WATER IN
YOUR VEHICLE IN CASE OF AN EMERGENCY. THE LATEST ROAD CONDITIONS FOR
THE STATE YOU ARE CALLING FROM CAN BE OBTAINED BY CALLING 5 1 1.
PERSONS SHOULD CONSIDER DELAYING ALL TRAVEL. IF TRAVEL IS ABSOLUTELY
NECESSARY, DRIVE WITH EXTREME CAUTION. CONSIDER TAKING A WINTER
STORM KIT ALONG WITH YOU, INCLUDING SUCH ITEMS AS TIRE CHAINS,
BOOSTER CABLES, FLASHLIGHT, SHOVEL, BLANKETS AND EXTRA CLOTHING.
ALSO TAKE WATER, A FIRST AID KIT, AND ANYTHING ELSE THAT WOULD HELP
YOU SURVIVE IN CASE YOU BECOME STRANDED.
IDZ006-191915-
/O.CON.KMSO.WW.Y.0049.251218T2000Z-251220T1800Z/
SOUTHERN CLEARWATER MOUNTAINS-
1126 PM PST WED DEC 17 2025
...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM NOON THURSDAY TO
10 AM PST SATURDAY...
* WHAT...SNOW EXPECTED. THERE IS A LIKELIHOOD OF MODERATE TO
ISOLATED MAJOR WINTER WEATHER IMPACTS. TOTAL SNOW ACCUMULATIONS OF
8 TO 14 INCHES IN THE HIGHER ELEVATIONS, INCLUDING LOLO PASS.
TOTAL ACCUMULATIONS OF 3 TO 7 INCHES ACROSS LOWER ELEVATIONS.
WINDS GUSTING AS HIGH AS 40 MPH.
* WHERE...DIXIE, ELK CITY, AND HIGHWAY 12 LOWELL TO LOLO PASS.
* WHEN...FROM NOON THURSDAY TO 10 AM PST SATURDAY.
* IMPACTS...FOR MODERATE WINTER WEATHER IMPACTS, EXPECT DISRUPTIONS
TO NORMAL ACTIVITIES. HAZARDOUS TRAVELING CONDITIONS. USE EXTRA
CAUTION WHILE DRIVING.
* ADDITIONAL DETAILS...SNOW LEVELS WILL BRIEFLY RISE ABOVE 5,000
FEET THURSDAY NIGHT BEFORE DROPPING BELOW 3,000 FEET FRIDAY
MORNING AS A COLD FRONT PASSES.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
SLOW DOWN AND USE CAUTION WHILE TRAVELING. THE LATEST ROAD
CONDITIONS FOR THE STATE YOU ARE CALLING FROM CAN BE OBTAINED BY
CALLING 5 1 1.
MTZ002-191915-
/O.CON.KMSO.WW.Y.0049.251218T2000Z-251220T1800Z/
WEST GLACIER REGION-
1226 AM MST THU DEC 18 2025
...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 1 PM THURSDAY TO
11 AM MST SATURDAY...
* WHAT...SNOW EXPECTED. THERE IS A LIKELIHOOD OF MODERATE TO
ISOLATED MAJOR WINTER WEATHER IMPACTS. TOTAL SNOW ACCUMULATIONS
BETWEEN 6 AND 12 INCHES FROM ESSEX TO MARIAS PASS. TOTAL SNOW
ACCUMULATIONS OF 2 AND 4 INCHES FOR LOWER ELEVATIONS, INCLUDING
WEST GLACIER. WINDS GUSTING AS HIGH AS 45 MPH.
* WHERE...MARIAS PASS, ESSEX, POLEBRIDGE, GLACIER NATIONAL PARK, BAD
ROCK CANYON, AND HIGHWAY 83 BIGFORK TO SWAN LAKE.
* WHEN...FROM 1 PM THURSDAY TO 11 AM MST SATURDAY.
* IMPACTS...FOR MODERATE WINTER WEATHER IMPACTS, EXPECT DISRUPTIONS
TO NORMAL ACTIVITIES. HAZARDOUS TRAVELING CONDITIONS. USE EXTRA
CAUTION WHILE DRIVING. GUSTY WINDS COULD BRING DOWN TREE BRANCHES.
* ADDITIONAL DETAILS...SNOW LEVELS WILL BRIEFLY RISE ABOVE 4,500
FEET THURSDAY NIGHT BEFORE DROPPING BELOW 3,000 FEET FRIDAY
MORNING AS A COLD FRONT PASSES.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
SLOW DOWN AND USE CAUTION WHILE TRAVELING. THE LATEST ROAD
CONDITIONS FOR THE STATE YOU ARE CALLING FROM CAN BE OBTAINED BY
CALLING 5 1 1.
MTZ004-191915-
/O.CON.KMSO.WW.Y.0049.251218T2000Z-251220T1800Z/
LOWER CLARK FORK REGION-
1226 AM MST THU DEC 18 2025
...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 1 PM THURSDAY TO
11 AM MST SATURDAY...
* WHAT...SNOW EXPECTED. THERE IS A LIKELIHOOD OF MODERATE WINTER
WEATHER IMPACTS. TOTAL SNOW ACCUMULATIONS OF 6 TO 12 INCHES AT
LOOKOUT PASS. WINDS GUSTING AS HIGH AS 35 MPH.
* WHERE...I-90 LOOKOUT PASS TO HAUGAN.
* WHEN...FROM 1 PM THURSDAY TO 11 AM MST SATURDAY.
* IMPACTS...FOR MODERATE WINTER WEATHER IMPACTS, EXPECT DISRUPTIONS
TO NORMAL ACTIVITIES. HAZARDOUS TRAVELING CONDITIONS. USE EXTRA
CAUTION WHILE DRIVING.
* ADDITIONAL DETAILS...SNOW LEVELS WILL BRIEFLY RISE ABOVE 5,000
FEET THURSDAY NIGHT WITH SNOW CHANGING TO RAIN AT LOOKOUT PASS.
SNOW LEVELS WILL DROP BELOW 3,000 FEET FRIDAY MORNING AS A COLD
FRONT PASSES WITH SNOW RESUMING.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
SLOW DOWN AND USE CAUTION WHILE TRAVELING. THE LATEST ROAD
CONDITIONS FOR THE STATE YOU ARE CALLING FROM CAN BE OBTAINED BY
CALLING 5 1 1.
AL
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page