Alert archive / Montana / Winter Storm Warnings in 2017

Winter Storm Warning 13, NWS Missoula, MT

October 1, 20176 counties in Montana

NWS Missoula, MT issued this winter storm warning at Oct 1, 2017, 2:25 PM MDT for 6 counties in Montana. It took effect at Oct 2, 2017, 6:00 AM MDT. It was in force for 24 hr. 6 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Oct 1, 2017, 2:25 PM MDT (20:25 UTC)
In effect from
Oct 2, 2017, 6:00 AM MDT
Expired
Oct 3, 2017, 6:00 AM MDT
In force
24 hr
Issued by
NWS Missoula, MT

Counties Deer Lodge County, MT, Flathead County, MT, Granite County, MT, Lake County, MT, Powell County, MT, Silver Bow County, MT

The radar

The Missoula radar (KMSX), 51 km from the middle of the area, began a volume at 20:26 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Oct 2, 9:36 PM MDTSNOW 2Anaconda, MTSTILL SNOWING. JUST SLUSHY ACCUMULATIONS ON SIDEWALKS, BUT TEMPERATURES ARE STILL DROPPING.
Oct 3, 1:32 AM MDTSNOW 4Anaconda, MT
Oct 3, 5:51 AM MDTSNOW 6Anaconda, MTUPDATE: AN ADDITIONAL 2 INCHES HAS BEEN MEASURED FROM EARLIER REPORTS, FOR A TOTAL OF 6.
Oct 3, 6:00 AM MDTSNOW 3Skalkaho Pass, MTSKALKAHO SUMMIT SNOTEL AT 7250 FT.
Oct 3, 6:00 AM MDTSNOW 58 S Janney, MTBASIN CREEK SNOTEL AT 7180 FT.
Oct 3, 6:00 AM MDTSNOW 76 Ssw Georgetown, MTREPORTED AT PETERSON MEADOWS SNOTEL AT 7200 FT.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 8.4 hours before the alert went out and 220 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Great_falls, MT at 12:00Z on 2017-10-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 12:00Z on 2017-10-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 22 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1536 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
22 m²/s²
0-3 km storm-relative helicity
93 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

784 
WWUS45 KMSO 012025
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
225 PM MDT Sun Oct 1 2017

MTZ002-022115-
/O.UPG.KMSO.WS.A.0008.171002T1200Z-171003T1200Z/
/O.NEW.KMSO.WS.W.0013.171002T1200Z-171003T1200Z/
West Glacier Region-
225 PM MDT Sun Oct 1 2017

...WINTER STORM WARNING IN EFFECT FROM 6 AM MONDAY TO 6 AM MDT
TUESDAY...

* WHAT...Heavy snow and blowing snow expected. Plan on difficult
  travel conditions. Below 4000 feet total snow accumulations of 1
  to 3 inches are expected. Above 4000 feet 3 to 5 inches, and 
  localized amounts up to 15 inches across the highest terrain. 
  Travelers over Marias Pass should plan for low visibility due to
  snow and blowing snow with 8 to 12 inches total accumulation by
  Tuesday morning.

* WHERE...Bad Rock Canyon, Essex, Highway 83 Bigfork to Swan 
  Lake, Marias Pass, and Polebridge.

* WHEN...From Monday morning through late Monday night.

* ADDITIONAL DETAILS...Winds gusting as high as 30 mph will cause
  areas of blowing and drifting snow, resulting in very poor
  visibility at times. Periods of near whiteout conditions are
  possible over Marias Pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions are expected. 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.

&&

$$

MTZ007-043-022115-
/O.NEW.KMSO.WW.Y.0029.171002T1500Z-171003T1200Z/
Butte/Blackfoot Region-Potomac/Seeley Lake Region-
225 PM MDT Sun Oct 1 2017

...WINTER WEATHER ADVISORY IN EFFECT FROM 9 AM MONDAY TO 6 AM MDT
TUESDAY...

* WHAT...Snow is expected. Plan on slippery road conditions,
  especially when traveling over MacDonald and Homestake Passes
  along with other mountain roads. Total snow accumulations of 2 
  to 4 inches, with localized amounts up to 7 inches, are 
  expected.

* WHERE...Butte, Georgetown Lake, Highway 12 Garrison to 
  Elliston, Homestake Pass, MacDonald Pass, Highway 200 Bonner 
  to Greenough, Highway 83 Seeley Lake to Condon, and I-90 East 
  Missoula to Bearmouth.

* WHEN...9 AM Monday to 6 AM Tuesday.

* ADDITIONAL DETAILS...Be prepared for reduced visibilities at 
  times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Be prepared for snow covered
roads and limited visibilities, and use caution while driving.
The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

IDZ006-MTZ006-020100-
/O.CON.KMSO.WW.Y.0028.000000T0000Z-171002T0100Z/
Southern Clearwater Mountains-Bitterroot/Sapphire Mountains-
225 PM MDT Sun Oct 1 2017 /125 PM PDT Sun Oct 1 2017/

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 7 PM MDT /6 PM
PDT/ THIS EVENING ABOVE 5000 FEET...

* WHAT...A wintry mixture of wet snow, graupel and sleet will continue
  into this evening. Plan on slippery road conditions. Additional
  wet snow accumulations of up to one inch are expected.

* WHERE...Dixie, Elk City, Highway 12 Lowell to Lolo Pass, 
  Highway 93 Sula to Lost Trail Pass, and Lolo Pass.

* WHEN...Until 7 PM today.

* ADDITIONAL DETAILS...Be prepared for reduced visibilities at 
  times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for wet snow means periods of wet snow
will cause primarily travel difficulties. Be prepared for snow
covered roads and limited visibilities, and use caution while
driving. The latest road conditions for the state you are calling
from can be obtained by calling 5 1 1.

&&

$$
4 follow-up statements
140 
WWUS45 KMSO 020038
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
638 PM MDT Sun Oct 1 2017

IDZ006-MTZ006-020145-
/O.EXP.KMSO.WW.Y.0028.000000T0000Z-171002T0100Z/
Southern Clearwater Mountains-Bitterroot/Sapphire Mountains-
638 PM MDT Sun Oct 1 2017 /538 PM PDT Sun Oct 1 2017/

...WINTER WEATHER ADVISORY WILL EXPIRE AT 7 PM MDT /6 PM PDT/
THIS EVENING ABOVE 5000 FEET...

Snow showers above 5000 feet will slowly diminish in coverage 
through the evening.

$$

MTZ002-030045-
/O.CON.KMSO.WS.W.0013.171002T1200Z-171003T1200Z/
West Glacier Region-
638 PM MDT Sun Oct 1 2017

...WINTER STORM WARNING REMAINS IN EFFECT FROM 6 AM MONDAY TO
6 AM MDT TUESDAY...

* WHAT...Heavy snow and blowing snow expected. Plan on difficult
  travel conditions. Below 4000 feet total snow accumulations of 1
  to 3 inches are expected. Above 4000 feet 3 to 5 inches, and 
  localized amounts up to 15 inches across the highest terrain. 
  Travelers over Marias Pass should plan for low visibility due to
  snow and blowing snow with 8 to 12 inches total accumulation by
  Tuesday morning.

* WHERE...Bad Rock Canyon, Essex, Highway 83 Bigfork to Swan 
  Lake, Marias Pass, and Polebridge.

* WHEN...6 AM Monday to 6 AM Tuesday.

* ADDITIONAL DETAILS...Be prepared for significant reductions in 
  visibility at times. Winds gusting as high as 30 mph will cause
  areas of blowing and drifting snow, resulting in very poor
  visibility at times. Periods of near whiteout conditions are
  possible over Marias Pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions are expected. 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.

&&

$$

MTZ007-043-030045-
/O.CON.KMSO.WW.Y.0029.171002T1500Z-171003T1200Z/
Butte/Blackfoot Region-Potomac/Seeley Lake Region-
638 PM MDT Sun Oct 1 2017

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 9 AM MONDAY TO
6 AM MDT TUESDAY...

* WHAT...Snow is expected. Plan on slippery road conditions,
  especially when traveling over MacDonald and Homestake Passes
  along with other mountain roads. Total snow accumulations of 2 
  to 4 inches, with localized amounts up to 7 inches, are 
  expected.

* WHERE...Butte, Georgetown Lake, Highway 12 Garrison to 
  Elliston, Homestake Pass, MacDonald Pass, Highway 200 Bonner 
  to Greenough, Highway 83 Seeley Lake to Condon, and I-90 East 
  Missoula to Bearmouth.

* WHEN...9 AM Monday to 6 AM Tuesday.

* ADDITIONAL DETAILS...Be prepared for reduced visibilities at 
  times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Be prepared for snow covered
roads and limited visibilities, and use caution while driving.
The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$
934 
WWUS45 KMSO 021842
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
1242 PM MDT Mon Oct 2 2017

MTZ007-031200-
/O.UPG.KMSO.WW.Y.0029.000000T0000Z-171003T1200Z/
/O.EXA.KMSO.WS.W.0013.000000T0000Z-171003T1200Z/
Butte/Blackfoot Region-
1242 PM MDT Mon Oct 2 2017

...WINTER STORM WARNING IN EFFECT UNTIL 6 AM MDT TUESDAY...

* WHAT...Heavy snow and blowing snow occurring over MacDonald Pass
  and terrain above 5000 feet. Plan on difficult travel 
  conditions. Additional snow accumulations of 1 to 3 inches, with
  localized amounts up to 6 inches, are expected.

* WHERE...Butte, Georgetown Lake, Highway 12 Garrison to 
  Elliston, Homestake Pass, and MacDonald Pass.

* WHEN...Until 6 AM Tuesday.

* ADDITIONAL DETAILS...Be prepared for significant reductions in
  visibility at times, especially over MacDonald Pass, due to
  blowing and drifting snow. Winds gusting up to 35 mph likely.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions are occurring. 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.

$$

MTZ002-031200-
/O.CON.KMSO.WS.W.0013.000000T0000Z-171003T1200Z/
West Glacier Region-
1242 PM MDT Mon Oct 2 2017

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM MDT
TUESDAY...

* WHAT...Heavy snow and blowing snow occurring. Plan on 
  difficult travel conditions. Additional snow accumulations of 
  3 to 5 inches, with localized amounts up to 14 inches, are 
  expected.

* WHERE...Bad Rock Canyon, Essex, Highway 83 Bigfork to Swan 
  Lake, Marias Pass, and Polebridge.

* WHEN...Until 6 AM Tuesday.

* ADDITIONAL DETAILS...Winds gusting as high as 35 mph will 
  cause areas of blowing and drifting snow.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow and blowing snow means severe
winter weather conditions are occurring. 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.

$$

MTZ043-031200-
/O.CON.KMSO.WW.Y.0029.000000T0000Z-171003T1200Z/
Potomac/Seeley Lake Region-
1242 PM MDT Mon Oct 2 2017

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 AM MDT
TUESDAY...

* WHAT...Snow occurring. Plan on slippery road conditions. 
  Additional snow accumulations of 1 to 3 inches, with localized 
  amounts up to 6 inches, are expected.

* WHERE...Highway 200 Bonner to Greenough, Highway 83 Seeley 
  Lake to Condon, and I-90 East Missoula to Bearmouth.

* WHEN...Until 6 AM Tuesday.

* ADDITIONAL DETAILS...Be prepared for reduced visibilities at 
  times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Be prepared for snow covered
roads and limited visibilities, and use caution while driving.
The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

$$
978 
WWUS45 KMSO 030954
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
354 AM MDT Tue Oct 3 2017

MTZ007-031500-
/O.CAN.KMSO.WS.W.0013.000000T0000Z-171003T1200Z/
/O.EXB.KMSO.WW.Y.0029.000000T0000Z-171003T1500Z/
Butte/Blackfoot Region-
354 AM MDT Tue Oct 3 2017

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 9 AM MDT THIS
MORNING...
...WINTER STORM WARNING IS CANCELLED...

* WHAT...Snow is still occurring, however not at the intensity we
  have experienced the past several hours. Still plan on slippery
  road conditions to continue through the early morning hours. 
  Additional snow accumulations of 1 to 2 inches are expected.

* WHERE...Butte, Georgetown Lake, Highway 12 Garrison to 
  Elliston, Homestake Pass, and MacDonald Pass.

* WHEN...Until 9 AM today.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Be prepared for snow covered
roads and limited visibilities, and use caution while driving.
The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

$$

MTZ002-031200-
/O.CON.KMSO.WS.W.0013.000000T0000Z-171003T1200Z/
West Glacier Region-
354 AM MDT Tue Oct 3 2017

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM MDT EARLY
THIS MORNING...

* WHAT...Light snow is still occurring, with slick conditions 
  still expected through the early morning hours, particularly for
  Marias Pass.

* WHERE...Bad Rock Canyon, Essex, Highway 83 Bigfork to Swan 
  Lake, Marias Pass, and Polebridge.

* WHEN...Until 6 AM today.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions are occurring. 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.

$$

MTZ043-031200-
/O.CON.KMSO.WW.Y.0029.000000T0000Z-171003T1200Z/
Potomac/Seeley Lake Region-
354 AM MDT Tue Oct 3 2017

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 AM MDT EARLY
THIS MORNING...

* WHAT...Light snow is still occurring, with slick conditions 
  still expected through the early morning hours.

* WHERE...Highway 200 Bonner to Greenough, Highway 83 Seeley 
  Lake to Condon, and I-90 East Missoula to Bearmouth.

* WHEN...Until 6 AM today.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Be prepared for snow covered
roads and limited visibilities, and use caution while driving.
The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

$$
090 
WWUS45 KMSO 031154
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
554 AM MDT Tue Oct 3 2017

MTZ002-031300-
/O.EXP.KMSO.WS.W.0013.000000T0000Z-171003T1200Z/
West Glacier Region-
554 AM MDT Tue Oct 3 2017

...WINTER STORM WARNING WILL EXPIRE AT 6 AM MDT EARLY THIS
MORNING...


$$

MTZ043-031300-
/O.EXP.KMSO.WW.Y.0029.000000T0000Z-171003T1200Z/
Potomac/Seeley Lake Region-
554 AM MDT Tue Oct 3 2017

...WINTER WEATHER ADVISORY WILL EXPIRE AT 6 AM MDT EARLY THIS
MORNING...


$$

MTZ007-031500-
/O.CON.KMSO.WW.Y.0029.000000T0000Z-171003T1500Z/
Butte/Blackfoot Region-
554 AM MDT Tue Oct 3 2017

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 9 AM MDT THIS
MORNING...

* WHAT...Snow is still occurring, however not at the intensity 
  we have experienced the past several hours. Still plan on 
  slippery road conditions to continue through the early morning 
  hours. Additional snow accumulations of 1 to 2 inches are 
  expected.

* WHERE...Butte, Georgetown Lake, Highway 12 Garrison to 
  Elliston, Homestake Pass, and MacDonald Pass.

* WHEN...Until 9 AM today.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Be prepared for snow covered
roads and limited visibilities, and use caution while driving.
The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

$$

The office that day

Everything else NWS Missoula, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 1, 1:14 PM MDTSpecial Weather StatementMSOLake31 min
Oct 1, 2:25 PM MDTWinter Weather AdvisoryMSODeer Lodge, Granite, Lake, Missoula, Powell, Silver Bow43 hr
Oct 1, 2:44 PM MDTLake Wind AdvisoryMSOFlathead, Lake, Sanders34 hr

Nearby

Winter Storm Warnings in Montana, 2017Every winter storm warning in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.