Daytime heating and an unstable southwest flow aloft brought thunderstorms to mainly central Oregon which started the High Cascades Complex Fire and the Hancock Fire.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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.
The episode as NWS PDT wrote it up.
Daytime heating and an unstable southwest flow aloft brought thunderstorms to mainly central Oregon which started the High Cascades Complex Fire and the Hancock Fire.
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 Pendleton, OR wrote its last area forecast discussion before the first event at Aug 23, 9:44 PM PST, 2 hours 16 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
1044 PM PDT TUE AUG 23 2011
UPDATED AVIATION DISCUSSION
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT...AN MID/UPPER LEVEL
LOW OFF THE SOUTHERN CALIFORNIA COAST WILL EVOLVE INTO AN OPEN SHORT
WAVE OVER THE NEXT 24 HOURS AS IT MOVES NORTHWARD. THE SHORT WAVE
WILL REACH SOUTHWEST OREGON WEDNESDAY AFTERNOON AND THEN MOVE
NORTHEASTWARD INTO CENTRAL OREGON WEDNESDAY EVENING AND THEN ACROSS
NORTHEAST OREGON OVERNIGHT. THIS DISTURBANCE WILL BRING SUBTROPICAL
MOISTURE INTO CENTRAL OREGON WEDNESDAY AFTERNOON/EVENING...WHICH
WILL COMBINE WITH DAYTIME SURFACE HEATING TO DESTABILIZE THE
ATMOSPHERE AND SET THE STAGE FOR SCATTERED THUNDERSTORMS WITH
ABUNDANT LIGHTNING WEDNESDAY AFTERNOON/EVENING IN CENTRAL...EAST
CENTRAL AND NORTHEAST OREGON AND IN THE BLUE MOUNTAINS OF SOUTHEAST
WASHINGTON. AS SUCH A FIRE WEATHER WATCH IS IN EFFECT FOR WEDNESDAY
AFTERNOON/EVENING FOR THUNDERSTORMS PRODUCING ABUNDANT LIGHTNING.
FOR MORE INFORMATION SEE PRODUCT PDXRFWPDT (WMO HEADER WWUS86 KPDT).
IN ADDITION...THERE WILL BE SUFFICIENT VERTICAL WIND SHEAR FOR SOME
THUNDERSTORMS IN CENTRAL OREGON TO BECOME STRONG OR POSSIBLY SEVERE
WEDNESDAY AFTERNOON/EVENING. THE MAIN THREAT WILL BE GUSTY WINDS AND
LARGE HAIL.
THE CHANCE FOR THUNDERSTORMS WILL SPREAD NORTH AND NORTHEAST ACROSS
NORTH CENTRAL AND NORTHEAST OREGON LATE WEDNESDAY AFTERNOON AND
EVENING. POLAN
&&
.AVIATION...06Z TAFS...VFR CONDITIONS WILL CONTINUE FOR THE NEXT 18
HOURS UNDER MOSTLY CLEAR SKIES. LOOK FOR INCREASING MID LEVEL CLOUDS
WITH BASES AROUND 12000-15000 FT AGL WEDNESDAY AFTERNOON SPREADING
NORTHWARD AS THE AFTERNOON WEARS ON. WINDS WILL BE LIGHT DRAINAGE
WINDS UP TO AROUND 8 KTS OVERNIGHT AND THEN INCREASE AND BECOME
UPSLOPE TERRAIN DRIVEN WINDS OF 5-15 KTS BY LATE WEDNESDAY MORNING.
NO REAL CHANGE ON WEDNESDAY OTHER THAN THE POSSIBILITY OF SOME CB
AND THUNDERSTORMS IN THE AFTERNOON AND EVENING. THIS WILL MAINLY
IMPACT KRDM...KBDN...KPDT AND KALW. POLAN
.PREVIOUS DISCUSSION... /ISSUED 231 PM PDT TUE AUG 23 2011/
SHORT TERM...TONIGHT THROUGH FRIDAY...A RIDGE OF HIGH PRESSURE WILL
DOMINATE THE AREA'S WEATHER WITH DRY CONDITIONS TONIGHT AND
WEDNESDAY MORNING.
THE CHALLENGE WILL BE WITH THE TIMING OF SOME MID LEVEL
MOISTURE...PWATS AROUND AN INCH...ALONG WITH AN UPPER LEVEL JET AND
A WEAK DISTURBANCE APPROACHING OREGON WEDNESDAY AFTERNOON. THE
COMBINATION OF THESE THREE WILL MAKE THE ATMOSPHERE INCREASINGLY
UNSTABLE AND TSRA ARE POSSIBLE AROUND CENTRAL OREGON WEDNESDAY
AFTERNOON. THIS AREA IS EXPECTED TO EXPAND IN COVERAGE WEDNESDAY
EVENING AND MOVE INTO THE BASIN/JOHN DAY HIGHLANDS AND BLUE/WALLOWA
MOUNTAIN AREAS BY WEDNESDAY EVENING. SOME OF THE STORMS COULD BECOME
STRONG AND PRODUCE GUSTY WINDS AND HAIL. THE CONVECTION SHOULD
DECREASE IN COVERAGE AND THE SHOWERS ARE EXPECTED TO PERSIST
OVERNIGHT.
BY THURSDAY THE MOISTURE CONTINUES AND WITH DAYTIME HEATING TSRA ARE
EXPECTED TO DEVELOP AGAIN ACROSS THE AREA. A LOW PRESSURE SYSTEM OFF
THE OR COAST WILL TRACK INLAND FRIDAY AND THEN ACROSS THE SOUTHERN
PORTIONS OF THE REGION FRIDAY NIGHT. THE LOCATION OF THE TRACK HAS
BEEN DRIFTING FURTHER SOUTH WITH EACH MODEL RUN. HOWEVER TSRA ARE
STILL POSSIBLE ALONG THE OR CASCADES FRIDAY AFTN/EVEN.
AFTERNOON HIGH TEMPERATURES ARE EXPECTED TO REMAIN ABOVE NORMAL
THROUGH THE END OF THE WEEK.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...AFTER A WEAK SYSTEM
MOVES THROUGH THE REGION FRIDAY NIGHT IT LOOKS THE A COOLER AND DRY
WEST TO NORTHWEST FLOW WILL ENSUE. THERE WILL LIKELY BE A COUPLE OF
WEAK FRONTAL SYSTEMS CLIPPING THE REGION WHICH WILL RESULT IN SOME
BREEZY PERIODS BUT OTHER THAN THAT NOT SEEING PRECIPITATION THREAT
DURING THE EXTENDED PERIOD.
FIRE WEATHER...A FIRE WEATHER WATCH IS IN EFFECT FOR WEDNESDAY
AFTERNOON AND EVENING FOR CENTRAL AND NORTHEAST OREGON. THIS WILL
COVER THE CENTRAL OREGON CASCADES NORTHEAST ACROSS THE JOHN DAY
HIGHLANDS AND BLUES TO WALLOWA COUNTY. THE WATCH IS IN EFFECT FOR
ABUNDANT LIGHTNING AND DRY FUELS. AN UPPER LEVEL TROUGH WILL BE
MOVING THROUGH THE AREA AND WILL GENERATE THUNDERSTORMS IN THE
AFTERNOON AND EVENING. SOME OF THE LONGER LIVED STORMS WILL PRODUCE
LAL 3 OR POSSIBLE 4. THE STORMS SHOULD DIMINISH OR MOVE EAST OUT THE
THE FORECAST AREA BY MIDNIGHT. 94
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 56 91 60 90 / 0 20 20 20
ALW 61 92 63 90 / 0 10 20 20
PSC 58 93 59 92 / 0 10 20 10
YKM 54 89 57 88 / 10 10 20 10
HRI 57 92 61 91 / 0 20 20 10
ELN 54 89 58 87 / 10 10 20 10
RDM 46 90 52 88 / 0 30 30 20
LGD 49 92 55 87 / 0 10 20 20
GCD 49 91 54 86 / 0 30 30 20
DLS 59 92 61 88 / 0 20 30 10
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING ORZ042-049-050-502-503-505>507-509.
WA...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING WAZ030.
&&
THREAT INDEX
WEDNESDAY : YELLOW
THURSDAY : GREEN
FRIDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
99/97/91HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
830 PM PDT TUE AUG 23 2011
UPDATED THIRD AND FOURTH PARAGRAPHS IN DAYS TWO THROUGH SEVEN
DISCUSSION.
ORZ041-042-044-049-050-502-503-505>509-WAZ024-026>030-520-521-
241415-
EASTERN COLUMBIA RIVER GORGE OF OREGON-NORTH CENTRAL OREGON-
LOWER COLUMBIA BASIN OF OREGON-GRANDE RONDE VALLEY-WALLOWA COUNTY-
NORTHERN BLUE MOUNTAINS OF OREGON-
SOUTHERN BLUE MOUNTAINS OF OREGON-JOHN DAY BASIN-OCHOCO-
JOHN DAY HIGHLANDS-
FOOTHILLS OF THE NORTHERN BLUE MOUNTAINS OF OREGON-
FOOTHILLS OF THE SOUTHERN BLUE MOUNTAINS OF OREGON-
EAST SLOPES OF THE OREGON CASCADES-
EASTERN COLUMBIA RIVER GORGE OF WASHINGTON-KITTITAS VALLEY-
YAKIMA VALLEY-LOWER COLUMBIA BASIN OF WASHINGTON-
FOOTHILLS OF THE BLUE MOUNTAINS OF WASHINGTON-
NORTHWEST BLUE MOUNTAINS OF WASHINGTON-
EAST SLOPES OF THE WASHINGTON CASCADES-SIMCOE HIGHLANDS-
830 PM PDT TUE AUG 23 2011
THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL AND NORTHEAST OREGON
AS WELL AS SOUTH CENTRAL AND SOUTHEAST WASHINGTON.
.DAY ONE...TONIGHT
THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.
HIGH PRESSURE BEGINS TO REBUILD OVER THE AREA TONIGHT WITH PARTLY
CLOUDY SKIES BECOMING MOSTLY CLEAR BY LATE AFTERNOON TO EARLY
EVENING.
.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY
WEDNESDAY AFTERNOON AND EVENING...FIRE WEATHER WATCH
FOR THUNDERSTORMS PRODUCING ABUNDANT LIGHTNING
BLUE MOUNTAINS OF WASHINGTON, NORTH CENTRAL OREGON SOUTH OF
SHANIKO, EAST SLOPES OF THE OREGON CASCADES, WALLOWA COUNTY,
GRANDE RONDE VALLEY, NORTHERN BLUE MOUNTAINS OF OREGON,
SOUTHERN BLUE MOUNTAINS OF OREGON, JOHN DAY BASIN,
OCHOCO-JOHN DAY HIGHLANDS
CONTACT YOUR LOCAL FOREST OR LAND MANAGEMENT AGENCY FOR
CURRENT FIRE DANGER CONDITIONS IN YOUR AREA.
WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT...CHANCE OF THUNDERSTORMS
EAST SLOPES OF THE WASHINGTON CASCADES, SIMCOE HIGHLANDS,
EASTERN COLUMBIA RIVER GORGE OF WASHINGTON, KITTITAS VALLEY,
YAKIMA VALLEY, LOWER COLUMBIA BASIN OF WASHINGTON, FOOTHILLS
OF THE BLUE MOUNTAINS OF WASHINGTON, NORTHWEST BLUE MOUNTAINS
OF WASHINGTON, EASTERN COLUMBIA RIVER GORGE OF OREGON, NORTH
CENTRAL OREGON, EAST SLOPES OF THE OREGON CASCADES, LOWER
COLUMBIA BASIN OF OREGON, FOOTHILLS OF THE NORTHERN BLUE
MOUNTAINS OF OREGON, FOOTHILLS OF THE SOUTHERN BLUE MOUNTAINS
OF OREGON
AN UPPER LEVEL LOW OFF THE SOUTHERN CALIFORNIA COAST WILL EVOLVE
INTO AN OPEN MID/UPPER LEVEL SHORT WAVE OVER THE NEXT 24 HOURS AS IT
MOVES NORTHWARD. THE SHORT WAVE WILL REACH SOUTHWEST OREGON
WEDNESDAY AFTERNOON AND THEN MOVE NORTHEASTWARD INTO CENTRAL OREGON
WEDNESDAY EVENING AND THEN ACROSS NORTHEAST OREGON OVERNIGHT. THE
SHORT WAVE WILL BRING SUBTROPICAL MOISTURE INTO CENTRAL OREGON
WEDNESDAY AFTERNOON/EVENING...WHICH WILL COMBINE WITH DAYTIME
SURFACE HEATING...WHICH WILL DESTABILIZE THE ATMOSPHERE AND SET THE
STAGE FOR SCATTERED THUNDERSTORMS WITH ABUNDANT LIGHTNING WEDNESDAY
AFTERNOON/EVENING IN CENTRAL...EAST CENTRAL AND NORTHEAST OREGON AND
IN THE BLUE MOUNTAINS OF SOUTHEAST WASHINGTON. AS SUCH A FIRE
WEATHER WATCH IS IN EFFECT FOR WEDNESDAY AFTERNOON/EVENING FOR
THUNDERSTORMS PRODUCING ABUNDANT LIGHTNING IN THE AREAS LISTED
ABOVE. FOR ADDITIONAL INFORMATION...SEE NWS PRODUCT PDXRFWPDT (WMO
HEADER WWUS86 KPDT).
IN ADDITION...THERE WILL BE SUFFICIENT VERTICAL WIND SHEAR FOR SOME
THUNDERSTORMS IN CENTRAL OREGON TO BECOME STRONG OR POSSIBLY SEVERE
WEDNESDAY AFTERNOON/EVENING. THE MAIN THREAT WILL ISOLATED DAMAGING
WINDS AND LARGE HAIL.
THE CHANCE FOR THUNDERSTORMS WILL SPREAD NORTH AND NORTHEAST ACROSS
NORTH CENTRAL AND NORTHEAST OREGON LATE WEDNESDAY AFTERNOON AND
EVENING.
HIGH PRESSURE WILL DOMINATE THE PACIFIC NORTHWEST FOR THE REST OF
THE WEEK...AND THROUGH THE WEEKEND INTO MONDAY. ALTHOUGH TIMING AND
POSITION ARE STILL UNCERTAIN THERE WILL BE A COUPLE OF EMBEDDED
DISTURBANCES IN THE UPSTREAM WESTERLY FLOW ALOFT OVER THE NORTHEAST
PACIFIC THAT MAY PRODUCE A SLIGHT CHANCE FOR THUNDERSTORMS ACROSS
CENTRAL OREGON AND THE MOUNTAINS OF NORTHEAST OREGON. OTHERWISE...
WARM TEMPERATURES WILL CONTINUE WITH MOSTLY DRY WEATHER.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE REQUIRED WEDNESDAY AFTERNOON AND EVENING
FOR THUNDERSTORMS...ESPECIALLY IN CENTRAL...NORTH CENTRAL AND
NORTHEAST OREGON.
WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
GRAPHICAL FORECASTS OF WEATHER HAZARDS OUT TO SEVEN DAYS
ARE DISPLAYED ON THE WORLD WIDE WEB AT:
WWW.WRH.NOAA.GOV/PDT/CURRENTHAZARDS/HWO.HTML
ALL LETTERS IN THE ABOVE URL ARE LOWER CASE.
POLANThe Portland,OR radar (KRTX), 189 km away, was scanning. The volume nearest the first event began at 00:44 UTC.
2 wildfire, 1 hail. Local standard time, as filed.
Fires in the High Cascades Complex on the Warm Spring Reservation were started by lightning and had burned 90,000 acres by the end of August.
Lightning sparked fires in the the Hancock Complex which had burned over 50,000 acres by the end of August.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2011Every state in 2011This day in weather historyWarnings in Oregon, August 2011
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: 329820, 329825, 329822.