During the late afternoon, thunderstorms developed in southern Umatilla and Morrow counties. These storms later collapsed as they moved north over lower terrain along the foothills of the Blue Mountains and the Lower Columbia Basin, leading to wind damage along the front edge of the gust front.
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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.
During the late afternoon, thunderstorms developed in southern Umatilla and Morrow counties. These storms later collapsed as they moved north over lower terrain along the foothills of the Blue Mountains and the Lower Columbia Basin, leading to wind damage along the front edge of the gust front.
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 Jul 12, 1:20 PM PST, 4 hours 40 minutes earlier.
NORTHEAST OREGON/SOUTHEAST WASHINGTON FORECAST DISCUSSION NATIONAL WEATHER SERVICE PENDLETON OR 220 PM PDT THU JUL 12 2001 ANOTHER ACTIVE NIGHT IS ON TAP FOR THE FORECAST AREA TONIGHT. TWO FEATURES WILL BRING CONVECTIVE WEATHER TO THE FORECAST AREA. THE UPPER LOW OVER SOUTHEAST OREGON WILL PROVIDE LOW LEVEL UPSLOPE FLOW TO THE EAST SLOPES OF THE WASHINGTON CASCADES. THIS LOCATION IS ALREADY UNSTABLE...HAVING HAD SOME SHOWERS EARLIER TODAY...AND CUMULUS CLOUDS ALREADY DEVELOPING AT THIS TIME. THE SECOND WAVE... WHICH IS NOT HANDLED WELL BY ANY OF THE MODELS...IS QUICKLY MAKING ITS WAY NORTHEAST TOWARD OREGON. THE IR AND WATER VAPOR BOTH SHOW GOOD CONVECTION ON THE FRONT END OF THIS WAVE OVER NORTHERN CALIFORNIA. THIS SECOND FEATURE WILL REACH THE OCHOCO MOUNTAINS AND JOHN DAY HIGHLANDS NEAR 00Z AND BE NEAR THE FOOTHILLS AND THE WALLOWAS BETWEEN 03-05Z. THIS WILL KEEP CONVECTIVE ACTIVITY IN THE EASTERN ZONES GOING THROUGH THE OVERNIGHT HOURS. WITH THE INSTABILITY PARAMETERS AS HIGH AS THEY ARE FROM CENTRAL OREGON THROUGH NORTHEAST OREGON...EXPECT SOME MARGINALLY SEVERE STORMS. SPC HAS PUT CENTRAL AND EASTERN OREGON IN THE SLIGHT RISK AREA FOR TODAY. AN UPPER TROUGH WILL SLOWLY APPROACH THE PACIFIC NORTHWEST BY THE END OF THE SHORT TERM AS THE UPPER RIDGE OVER THE SOUTHWEST US BEGINS TO SHIFT EAST. SINCE THE TROUGH TAKES ITS TIME APPROACHING THE COAST...A STRONG MARINE PUSH IS NOT EVIDENT. HOWEVER EXPECT WEAK LITTLE WAVES OF COOLER MARINE AIR TO MOVE THROUGH THE FORECAST AREA STARTING FRIDAY EVENING. WITH THE SOUTHWEST FLOW APPROACHING...THE UNSTABLE AIR WILL SHIFT EVER SO SLOWLY EAST AND SOUTH OVER THE NEXT 36-48 HOURS. THIS WILL RELEGATE THE THUNDERSTORM THREAT TO MAINLY OVER THE WALLOWAS...JOHN DAY HIGHLANDS AND BAKER COUNTY BY SATURDAY. TEMPERATURES WILL REMAIN PERSISTENT FOR ONE MORE DAY...THEN COOL SLIGHTLY SATURDAY. THINK GUIDANCE IS A BIT TOO LOW FOR SATURDAY...SO HAVE ADJUSTED ACCORDINGLY. MEAD IN THE EXTENDED...AS THE UPPER LEVEL PATTERN SHIFTS EAST THIS WEEKEND...THE UPPER TROUGH IN THE GULF OF ALASKA WILL SHIFT INTO THE PACNW BY MONDAY. THUS CONDITIONS WILL REMAIN UNSETTLED...BUT WILL BE 10 TO 15 DEGREES COOLER AS MARINE AIR SETTLES OVER THE AREA. THIS MOIST MARINE AIR SHOULD REDUCE THE INSTABILITY ACROSS THE AREA... AND ONLY EXPECT SHOWERY PRECIP WITH NO THUNDERSTORMS. GKH PDT 5221 ALW 5221 PSC 2110 YKM 3100 .KPDT...WSR-88D...VCP21/CSR21...OPERATIONAL. .KPDT...NONE.
The Pendleton radar (KPDT), 37 km away, was scanning. The volume nearest the first event began at 02:02 UTC.
2 thunderstorm wind. Local standard time, as filed.
Estimated wind gusts between 50 and 60 mph broke large limbs off many trees around Hermiston.
Several wind sensors located adjacent to the Umatilla Army Depot received severe wind gusts. 3 sites measured gusts of 70, 65 and 59 mph respectively.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2001Every state in 2001This day in weather historyWarnings in Oregon, July 2001
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: 5260840, 5260841.