Alert archive / Washington / Winter Storm Warnings in 2021

Winter Storm Warning 11, NWS Spokane, WA

December 7, 2021Chelan County, Washington

NWS Spokane, WA issued this winter storm warning at Dec 7, 2021, 2:14 PM PST for Chelan County, Washington. It took effect at Dec 8, 2021, 4:00 AM PST. It was in force for 23 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Dec 7, 2021, 2:14 PM PST (22:14 UTC)
In effect from
Dec 8, 2021, 4:00 AM PST
Expired
Dec 9, 2021, 2:45 AM PST
In force
23 hr
Issued by
NWS Spokane, WA

County Chelan County, WA

The radar

The Seattle radar (KATX), 144 km from the middle of the area, began a volume at 22:16 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.

The nearest sounding before it

Quillayute State, WA (KUIL), launched 12:00Z, 10.2 hours before the alert went out and 289 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, Quillayute State, WA at 12:00Z on 2021-12-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Quillayute State, WA at 12:00Z on 2021-12-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 127 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
575 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
127 m²/s²
0-3 km storm-relative helicity
180 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

516 
WWUS46 KOTX 072214
WSWOTX

URGENT - WINTER WEATHER MESSAGE
National Weather Service Spokane WA
214 PM PST Tue Dec 7 2021

...LIGHT WINTRY MIX FOR NORTHEASTERN WASHINGTON AND NORTH IDAHO 
OVERNIGHT INTO WEDNESDAY MORNING.  HEAVY SNOW ALONG THE CASCADE 
CREST WEDNESDAY INTO THURSDAY. ...

WAZ048-080800-
/O.NEW.KOTX.WS.W.0011.211208T1200Z-211209T1800Z/
Western Chelan County-
Including the cities of Stevens Pass
214 PM PST Tue Dec 7 2021

...WINTER STORM WARNING IN EFFECT FROM 4 AM WEDNESDAY TO 10 AM PST 
THURSDAY FOR THE CASCADE CREST & STEVENS PASS...

* WHAT...Heavy snow expected Cascade Crest & Stevens Pass. Total 
  snow accumulations between 8 and 15 inches. Winds gusting 35 to as 
  high as 50 mph.

* WHERE...Stevens Pass.

* WHEN...From 4 AM Wednesday to 10 AM PST Thursday.

* IMPACTS...Roads will likely become slick and snow covered. Travel 
  could be very difficult. Gusty winds could bring down tree 
  branches and create blowing snow.

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.

&&

$$

IDZ001-WAZ037-080800-
/O.NEW.KOTX.WW.Y.0037.211208T0800Z-211208T1500Z/
Northern Panhandle-Northeast Mountains-
Including the cities of Eastport, Sandpoint, Colville, Northport,
Bonners Ferry, Orin-Rice Road, Athol, Newport, Flowery Trail
Road, Chewelah, Deer Park, Springdale-Hunters Road, Kettle Falls,
Schweitzer Mountain Road, and Priest River
214 PM PST Tue Dec 7 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 7 AM 
PST WEDNESDAY...

* WHAT...Light wintry mix of snow and freezing rain expected. Total 
  snow accumulations up to two inches.  Ice accumulations of a glaze 
  to two hundreths possible.

* WHERE...Eastport, Sandpoint, Colville, Northport, Bonners Ferry, 
  Orin-Rice Road, Athol, Newport, Flowery Trail Road, Chewelah, Deer 
  Park, Springdale-Hunters Road, Kettle Falls, Schweitzer Mountain 
  Road, and Priest River.

* WHEN...From Midnight tonight to 7 AM PST Wednesday.

* IMPACTS...Roads, and especially bridges and overpasses, will 
  likely become slick. Plan on slippery road conditions. The 
  hazardous conditions could impact the Wednesday morning commute.

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.

&&

$$

SB
5 follow-up statements
175 
WWUS46 KOTX 080746
WSWOTX

URGENT - WINTER WEATHER MESSAGE
National Weather Service Spokane WA
1146 PM PST Tue Dec 7 2021

...LIGHT WINTRY MIX FOR NORTHEASTERN WASHINGTON AND NORTH IDAHO 
OVERNIGHT INTO WEDNESDAY MORNING. HEAVY SNOW ALONG THE CASCADE CREST 
WEDNESDAY INTO THURSDAY...

WAZ048-081600-
/O.CON.KOTX.WS.W.0011.211208T1200Z-211209T1800Z/
Western Chelan County-
Including the cities of Stevens Pass
1146 PM PST Tue Dec 7 2021

...WINTER STORM WARNING REMAINS IN EFFECT FROM 4 AM WEDNESDAY TO 10 
AM PST THURSDAY CASCADE CREST & STEVENS PASS...

* WHAT...Heavy snow expected Cascade Crest & Stevens Pass. Total 
  snow accumulations between 8 and 15 inches. Winds gusting 35 to as 
  high as 50 mph.

* WHERE...Stevens Pass.

* WHEN...From 4 AM Wednesday to 10 AM PST Thursday.

* IMPACTS...Roads will likely become slick and snow covered. Travel 
  could be very difficult. Gusty winds could bring down tree 
  branches and create blowing snow.

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.

&&

$$

IDZ001-WAZ037-081500-
/O.CON.KOTX.WW.Y.0037.211208T0800Z-211208T1500Z/
Northern Panhandle-Northeast Mountains-
Including the cities of Eastport, Sandpoint, Colville, Northport,
Bonners Ferry, Orin-Rice Road, Athol, Newport, Flowery Trail
Road, Chewelah, Deer Park, Springdale-Hunters Road, Kettle Falls,
Schweitzer Mountain Road, and Priest River
1146 PM PST Tue Dec 7 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 7 AM PST 
WEDNESDAY...

* WHAT...Light wintry mix of snow and freezing rain or drizzle 
  expected. Total snow accumulations up to two inches. Ice 
  accumulations of a glaze to two hundreths possible.

* WHERE...Eastport, Sandpoint, Colville, Northport, Bonners Ferry, 
  Orin-Rice Road, Athol, Newport, Flowery Trail Road, Chewelah, Deer 
  Park, Springdale-Hunters Road, Kettle Falls, Schweitzer Mountain 
  Road, and Priest River.

* WHEN...Until 7 AM PST Wednesday.

* IMPACTS...Roads, and especially bridges and overpasses, will 
  likely become slick. Plan on slippery road conditions. The 
  hazardous conditions could impact the Wednesday morning commute.

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.

&&

$$

SVH
762 
WWUS46 KOTX 081445
WSWOTX

URGENT - WINTER WEATHER MESSAGE
National Weather Service Spokane WA
645 AM PST Wed Dec 8 2021

IDZ001-WAZ037-081545-
/O.EXP.KOTX.WW.Y.0037.000000T0000Z-211208T1500Z/
Northern Panhandle-Northeast Mountains-
Including the cities of Eastport, Sandpoint, Colville, Northport,
Bonners Ferry, Orin-Rice Road, Athol, Newport, Flowery Trail
Road, Chewelah, Deer Park, Springdale-Hunters Road, Kettle Falls,
Schweitzer Mountain Road, and Priest River
645 AM PST Wed Dec 8 2021

...WINTER WEATHER ADVISORY WILL EXPIRE AT 7 AM PST THIS MORNING...

Temperatures have slowly moderated through the night with less of a 
risk of freezing rain or freezing drizzle. Isolated snow showers at 
times this morning, but not enough to impact travel.

$$

WAZ048-082245-
/O.CON.KOTX.WS.W.0011.000000T0000Z-211209T1800Z/
Western Chelan County-
Including the cities of Stevens Pass
645 AM PST Wed Dec 8 2021

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 10 AM PST THURSDAY 
CASCADE CREST & STEVENS PASS...

* WHAT...Heavy snow Cascade Crest & Stevens Pass. Additional snow 
  accumulations between 3 and 13 inches. Winds gusting 35 to as high 
  as 50 mph.

* WHERE...Stevens Pass.

* WHEN...Until 10 AM PST Thursday.

* IMPACTS...Roads will likely become slick and snow covered. Travel 
  could be very difficult. Gusty winds could bring down tree 
  branches and create blowing snow.

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.

&&

$$

SVH
835 
WWUS46 KOTX 081906
WSWOTX

URGENT - WINTER WEATHER MESSAGE
National Weather Service Spokane WA
1106 AM PST Wed Dec 8 2021

WAZ048-090315-
/O.CON.KOTX.WS.W.0011.000000T0000Z-211209T1800Z/
Western Chelan County-
Including the cities of Stevens Pass
1106 AM PST Wed Dec 8 2021

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 10 AM PST THURSDAY 
CASCADE CREST & STEVENS PASS...

* WHAT...Heavy snow Cascade Crest & Stevens Pass. Additional snow 
  accumulations between 8 and 12 inches from Wednesday afternoon to 
  Thursday morning.

* WHERE...Stevens Pass.

* WHEN...Until 10 AM PST Thursday.

* IMPACTS...Motorists should plan on winter driving conditions over 
  Stevens Pass.

* ADDITIONAL DETAILS...A persistent convergence zone will continue 
  to impact the area between and including Stevens and Snoqualmie 
  Pass. Snowfall rates of 1 to 2 inches per hour remain possible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

The latest road conditions for the state you are calling from can be 
obtained by calling 5 1 1.

&&

$$

GKOCH
795 
WWUS46 KOTX 090240
WSWOTX

URGENT - WINTER WEATHER MESSAGE
National Weather Service Spokane WA
640 PM PST Wed Dec 8 2021

WAZ048-091445-
/O.CON.KOTX.WS.W.0011.000000T0000Z-211209T1800Z/
Western Chelan County-
Including the cities of Stevens Pass
640 PM PST Wed Dec 8 2021

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 10 AM PST THURSDAY 
CASCADE CREST & STEVENS PASS...

* WHAT...Heavy snow Cascade Crest & Stevens Pass. Additional snow 
  accumulations between 5 and 10 inches through Thursday morning. 
  Winds gusting as high as 35 mph.

* WHERE...Stevens Pass.

* WHEN...Until 10 AM PST Thursday.

* IMPACTS...Roads, and especially bridges and overpasses, will 
  likely become slick and hazardous. Travel could be very difficult. 
  The hazardous conditions could impact the Thursday morning commute.

* ADDITIONAL DETAILS...A persistent convergence zone will continue 
  to impact the area between and including Stevens and Snoqualmie 
  Pass. Snowfall rates of 1 to 2 inches per hour remain possible.

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.



&&

$$

JCLEV
872 
WWUS46 KOTX 091045
WSWOTX

URGENT - WINTER WEATHER MESSAGE
National Weather Service Spokane WA
245 AM PST Thu Dec 9 2021

...SNOW SHOWERS THURSDAY FOLLOWED BY A WINTER STORM BRINGING HEAVY 
SNOW FRIDAY NIGHT THROUGH SATURDAY...

.Snow showers will continue over the Cascade crest Thursday into 
Thursday evening at the Cascades crest resulting in difficult travel 
at times over Stevens Pass. Snow showers will also develop over the 
Central Panhandle Mountains Thursday afternoon and evening with 
bursts of heavy snow at times. A winter storm will then move into 
the Cascades by Friday evening with snow becoming heavy Friday night 
through Saturday. Travel is not recommended over Stevens Pass during 
this winter storm. Snow is expected to decrease overnight Saturday 
into Sunday.

WAZ048-092330-
/O.CAN.KOTX.WS.W.0011.000000T0000Z-211209T1800Z/
/O.NEW.KOTX.WW.Y.0038.211209T1045Z-211210T0600Z/
/O.NEW.KOTX.WS.A.0007.211211T0600Z-211212T0600Z/
Western Chelan County-
Including the cities of Holden Village, Stehekin, and Stevens
Pass
245 AM PST Thu Dec 9 2021

...WINTER STORM WARNING IS CANCELLED...
...WINTER WEATHER ADVISORY REPLACING WINTER STORM WARNING IN EFFECT 
UNTIL 10 PM PST THIS EVENING...
...WINTER STORM WATCH IN EFFECT FROM FRIDAY EVENING THROUGH SATURDAY 
EVENING...

* WHAT...For the Winter Weather Advisory, snow at Cascade Crest and 
  Stevens Pass. Additional snow accumulations between 6 and 12 
  inches. For the Winter Storm Watch, heavy snow possible. Total 
  snow accumulations between 1 to 2 feet possible. Winds could gust 
  as high as 35 mph.

* WHERE...Stevens Pass, Holden Village, and Stehekin.

* WHEN...For the Winter Weather Advisory, until 10 PM PST this 
  evening. For the Winter Storm Watch, from Friday evening through 
  Saturday evening.

* IMPACTS...Snow will make for difficult travel conditions through 
  Thursday evening. Heavy snow for Friday night through Saturday 
  could result in very difficult to impossible travel conditions. 
  Travel over Stevens Pass is not advised during this period of 
  heavy snow.

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.

Persons should consider delaying all travel Friday night through 
Saturday. 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.

&&

$$

IDZ004-092330-
/O.NEW.KOTX.WW.Y.0038.211209T2100Z-211210T0800Z/
Central Panhandle Mountains-
Including the cities of Wallace, Osburn, Dobson Pass, Kellogg,
Fernwood, Lookout Pass, and Mullan
245 AM PST Thu Dec 9 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 1 PM THIS AFTERNOON TO 
MIDNIGHT PST TONIGHT...

* WHAT...Snow expected. Total snow accumulations between 2 and 6 
  inches.

* WHERE...Wallace, Osburn, Dobson Pass, Kellogg, Fernwood, Lookout 
  Pass, and Mullan.

* WHEN...From 1 PM this afternoon to Midnight PST tonight.

* IMPACTS...Plan on slippery road conditions.

* ADDITIONAL DETAILS...Bursts of heavy snow will be possible with 
  snow accumulations of up to 1 inch per hour. Plan on rapid changes 
  to weather conditions for the late afternoon and evening travel 
  period over Lookout Pass.

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.

&&

$$

WAZ047-049-092330-
/O.NEW.KOTX.WS.A.0007.211211T0600Z-211212T0600Z/
Central Chelan County-Western Okanogan County-
Including the cities of Winthrop, Plain, Leavenworth, Methow,
Twisp, Loup Loup Pass, Conconully, and Mazama
245 AM PST Thu Dec 9 2021

...WINTER STORM WATCH IN EFFECT FROM FRIDAY EVENING THROUGH SATURDAY 
EVENING...

* WHAT...Heavy snow possible. Total snow accumulations between 3 and 
  7 inches possible in the valleys and 8 to 18 inches possible in 
  the mountains. Winds could gust as high as 35 mph.

* WHERE...Winthrop, Plain, Leavenworth, Methow, Twisp, Loup Loup 
  Pass, Conconully, and Mazama.

* WHEN...From Friday evening through Saturday evening.

* IMPACTS...Travel could be very difficult to impossible. 

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.

Monitor the latest forecasts for updates on this situation.

&&

$$

SVH

The office that day

Everything else NWS Spokane, WA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 7, 5:35 AM PSTWinter Weather AdvisoryOTXLincoln, Pend Oreille, Spokane, Stevens, Whitman5 hr
Dec 7, 2:14 PM PSTWinter Weather AdvisoryOTXPend Oreille, Spokane, Stevens17 hr

Nearby

Winter Storm Warnings in Washington, 2021Every winter storm warning in 2021

Sources

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