Debris Flow, East Slopes Northern Cascades
- When
- January 15, 4:30 PM PST
- Where
- East Slopes Northern Cascades forecast zone
- Reported by
- Newspaper
Debris Flow in Washington, January 15, 2010
A large boulder slid down a hillside onto Highway 2 just west of Leavenworth causing extensive damage to the roadway. The boulder was 25 feet long and 20 feet wide, and created a hole in the highway three to five feet deep, and cracks 75 to 100 feet long.
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
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 OTX wrote it up.
A large boulder slid down a hillside onto Highway 2 just west of Leavenworth causing extensive damage to the roadway. The boulder was 25 feet long and 20 feet wide, and created a hole in the highway three to five feet deep, and cracks 75 to 100 feet long.
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 Spokane, WA wrote its last area forecast discussion before the first event at Jan 15, 2:44 PM PST, 1 hour 46 minutes earlier.
Area forecast discussion, Jan 15, 2:44 PM PST, 1 hour 46 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 244 PM PST FRI JAN 15 2010 .SYNOPSIS...AN INCREASINGLY MOIST AND WET AIRMASS WILL MOVE INTO THE INLAND NORTHWEST TONIGHT AND LINGER THROUGH THE WEEKEND. THE FOCUS OF THE HEAVIEST PRECIPITATION WILL BE ALONG THE INTERSTATE 90 CORRIDOR FROM SPOKANE EAST THROUGH IDAHO. FROZEN GROUND ACROSS THE REGION WILL PRODUCE PONDING AND GENERALLY MINOR FLOODING FROM THIS ADDITIONAL PRECIPITATION. && .DISCUSSION... TONIGHT THRU MON...THE BIGGEST CHANGE HAS BEEN TO DECREASE PCPN AMNTS ACROSS NRN WA AND THE FAR N ID PANHANDLE ZONES FOR TONIGHT AND SAT...TAKING INTO ACCOUNT THE FASTER EWD PROGRESSION OF THE NRN END OF THE COLDFNT CURRENTLY JUST PASSING THROUGH THE PUGET SOUND. THE GOOD NEWS IS THAT THIS QUICKER TREND WILL KEEP EXPECTED PCPN AMNTS ACROSS THE ALREADY SATURATED SOILS OVER NE WA AND THE N ID PANHANDLE LOWER THAN WHAT WAS PREVIOUS FCST THROUGH SAT. HOWEVER...WE STILL EXPECT THE SRN END OF THE FRONT TO STALL OVER THE SPOKANE AND ID PANHANDLE AREA BEFORE LIFTING SLOWLY NWD AS A WRMFNT LATE SAT AND SAT NT...PRODUCING ADDITIONAL MODERATE VALLEY RAIN AND MTN SNOW FOR ZONES N AND E OF SPOKANE. FOLLOWING THIS...TWO STRONG AND QUICK-MOVING SHORT-WAVES TROFS WILL IMPACT THE REGION...ONE SUNDAY AND THE OTHER SUNDAY NIGHT AS A STRENGTHENING EPAC ZONAL JET DRIVES A NUMBER OF WAVES INTO THE WRN CONUS. BZ FOR HYDRO CONCERNS... WE'RE NOT EXPECTING A BIG IMPACT AS FAR AS FLOODING POTENTIAL FOR THE SPOKANE AREA. FCST PCPN AMNTS AREN'T IMPRESSIVE EITHER FOR THE NE WA AND N ID...BUT CALLS TO SPOTTERS FROM BONNER COUNTY WEST THROUGH STEVENS COUNTY ALL CONFIRM NUMEROUS FIELDS UNDER WATER. SO IT WILL TAKE VERY LITTLE ADDITIONAL PCPN TO PRODUCE A SECOND ROUND OF FLOODING. THE FLOOD WARNING COVERS THIS THREAT. BZ MONDAY NIGHT TO FRIDAY...GUIDANCE SHOWS A BROAD TROUGH CARVING ITSELF OUT NEAR THE PACIFIC COAST...WHILE A TRAIN OF EMBEDDED DISTURBANCES COME THROUGH THE WEST. ONE PASSES OVER THE INLAND NW EVERY 18-30 HRS IN THE SWLY FLOW...THOUGH THEIR BRUNT STAYS SOUTH. PRECISE TIMING IS APT TO WOBBLE. ATTM LOOSE AGREEMENT SUPPORTS HIGHEST PRECIPITATION CHANCES TUESDAY AND THURSDAY NIGHT/FRIDAY. YET A RISK WILL BE FOUND EACH DAY. THROUGH THURSDAY 850 TEMPS/WET-BULB ZERO HEIGHTS SUPPORT DAYTIME SNOW LEVELS BTWN 3-5KFT. SOME SNOW MAY REACH VALLEY FLOORS AT NIGHT BUT ACCUMULATIONS (IF ANY) LOOK LIGHT. THURS NT TO FRIDAY MOST GUIDANCE INDICATES 850 TEMPS/WET-BULB ZERO HEIGHTS DIPPING... WITH DAYTIME SNOW LEVELS BTWN 2-3KFT. HOWEVER IT IS TOO EARLY TO BE DEFINITIVE ON DETAILS OTHER THAN TO SAY THERE WILL BE A BETTER CHANCE OF ACCUMULATING SNOWS IN VALLEY/BASIN AREAS LATE NEXT WEEK. /JCOTE && .AVIATION... 00Z TAFS...A COLD FRONT NEAR THE NRN CSCDS WILL SLIDE ESE AND STALL ACROSS NRN ID TO NW OR...WHILE A SFC LOW MOVES UP FROM THE SOUTH. THIS WILL LEAD TO INCREASING VALLEY RAIN AND MAINLY MOUNTAIN SNOW OVER WA AND ID TONIGHT INTO SATURDAY. THIS WILL LEAD TO CIGS AND VIS DETERIORATING TO MVFR AND EVENTUALLY IFR LEVELS AT MOST TAF SITES TOWARD 03-06Z. AN EXCEPTION WILL BE KPUW AND KLWS...WHICH ARE EXPECTED TO REMAIN ON FRINGES OF THE LOWER CIGS AND STEADIER PRECIPITATION CHANCES UNTIL AFTER 09-14Z AND EVEN THEN PRIMARILY MVFR CIGS ARE EXPECTED. /JCOTE && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 37 41 35 45 34 42 / 90 90 70 20 50 50 COEUR D'ALENE 36 41 34 44 34 42 / 100 90 70 20 50 50 PULLMAN 37 43 36 46 36 44 / 50 60 30 20 50 40 LEWISTON 40 48 38 49 38 49 / 20 40 10 10 40 40 COLVILLE 34 40 33 42 34 41 / 90 70 70 50 60 50 SANDPOINT 35 39 33 42 32 40 / 100 80 70 30 60 50 KELLOGG 33 40 34 41 34 40 / 100 90 60 20 60 50 MOSES LAKE 35 42 34 45 33 42 / 60 40 30 50 50 20 WENATCHEE 34 37 33 40 31 39 / 50 40 30 50 60 20 OMAK 33 37 35 39 31 38 / 40 30 30 60 60 40 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...FLOOD WARNING THROUGH SATURDAY FOR PARTS OF THE NORTHERN PANHANDLE. WA...FLOOD WARNING THROUGH SATURDAY FOR PARTS OF THE NORTHEAST MOUNTAINS. && WEATHER OBSERVATIONS CAN BE SUBMITTED THROUGH YOUR TWITTER ACCOUNT. GO TO HTTP://WWW.SRH.NOAA.GOV/SRH/TWITTER/TWITTER.PHP TYPED ALL IN LOWER CASE IN YOUR BROWSER AND TELL THE NWS ABOUT THE WEATHER IN YOUR AREA.
Hazardous weather outlook, Jan 15, 10:52 AM PST, 5 hours 38 minutes before
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE SPOKANE WA 1052 AM PST FRI JAN 15 2010 IDZ001-WAZ037-161900- NORTHERN PANHANDLE-NORTHEAST MOUNTAINS- 1052 AM PST FRI JAN 15 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH IDAHO AND NORTHEAST WASHINGTON. .DAY ONE...TODAY AND TONIGHT A FLOOD WARNING IS IN EFFECT UNTIL SATURDAY AFTERNOON. A MOIST FRONTAL BOUNDARY WILL MOVE INTO THE REGION TODAY AND STALL ACROSS THE REGION TONIGHT THROUGH SATURDAY NIGHT. THIS WEATHER SYSTEM WILL PRODUCE MODERATE TO HEAVY RAIN. ONE HALF TO ONE INCH OF RAIN IS EXPECTED BY SATURDAY NIGHT...WITH FLOODING AND PONDING OF WATER LIKELY. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY A FLOOD WARNING IS IN EFFECT UNTIL SATURDAY AFTERNOON. THE WARM MOIST WEATHER SYSTEM WILL CONTINUE THROUGH EARLY SUNDAY AND RESULT IN MODERATE RAIN ACROSS THE REGION. ONE HALF TO ONE INCH WILL BE LIKELY BY SATURDAY NIGHT BELOW 4000 FEET. FLOODING AND PONDING OF WATER IS EXPECTED. IDZ002>004-026-027-WAZ031>036-038-041>044-161900- COEUR D'ALENE AREA-IDAHO PALOUSE-CENTRAL PANHANDLE MOUNTAINS- LEWISTON AREA-LEWIS AND SOUTHERN NEZ PERCE COUNTIES- NORTHEAST BLUE MOUNTAINS-LOWER GARFIELD AND ASOTIN COUNTIES- WASHINGTON PALOUSE-MOSES LAKE AREA-UPPER COLUMBIA BASIN- SPOKANE AREA-OKANOGAN HIGHLANDS-WENATCHEE AREA- EAST SLOPES NORTHERN CASCADES-OKANOGAN VALLEY-WATERVILLE PLATEAU- 1052 AM PST FRI JAN 15 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH IDAHO... NORTH CENTRAL IDAHO...CENTRAL WASHINGTON...EAST CENTRAL WASHINGTON...NORTH CENTRAL WASHINGTON...NORTHEAST WASHINGTON AND SOUTHEAST WASHINGTON. .DAY ONE...TODAY AND TONIGHT A WARM MOIST STORM SYSTEM WILL RESULT IN MODERATE RAIN ACROSS THE REGION THROUGH SATURDAY NIGHT. RAINFALL AMOUNTS BETWEEN ONE QUARTER AND ONE HALF INCH ARE POSSIBLE BY SATURDAY NIGHT. MINOR FLOODING AND PONDING OF WATER ON FLAT SURFACES IS POSSIBLE .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY MINOR FLOODING AND PONDING OF WATER ON FLAT SURFACES IS POSSIBLE SATURDAY THROUGH THE WEEKEND AS THE WARM...MOIST STORM SYSTEM LINGERS OVER THE REGION. ADDITIONAL RAINFALL AMOUNTS OF A TENTH TO HALF AN INCH WILL BE POSSIBLE THROUGH SUNDAY NIGHT.
Event by event
1 debris flow. Local standard time, as filed.
What these are
- Debris Flow
- A fast-moving slurry of mud, rock and debris, usually on a slope soaked by heavy rain or stripped by a fire.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Flooding in Texas, January 15, 2010
- High Wind in Washington, January 15, 2010
- Astronomical Low Tide and Strong Wind in Louisiana, January 15, 2010
- Heavy Snow and High Wind in Alaska, January 15 to 17, 2010
- High Wind in Oregon, January 15, 2010
- Flash Flood in Texas, January 15, 2010
- High Wind in Washington, January 15, 2010
- High Wind in Oregon, January 15, 2010
More
Every storm in Washington in 2010Every state in 2010This day in weather historyWarnings in Washington, January 2010
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: 207442.