Numerous human and lightning caused wildfires started in August after prolonged heat at the very end of July and numerous rounds of thunderstorms in early to middle August. Another hot spell occurred in mid August increasing fire weather concerns.
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.
Numerous human and lightning caused wildfires started in August after prolonged heat at the very end of July and numerous rounds of thunderstorms in early to middle August. Another hot spell occurred in mid August increasing fire weather concerns.
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 11, 8:11 PM PST, 3 hours 49 minutes earlier.
Area Forecast Discussion National Weather Service Pendleton OR 911 PM PDT Tue Aug 11 2020 .UPDATE...Winds have begun in decrease and relative humidity values have increased a bit earlier this evening than expected. Therefore the Red Flag Warning has been cancelled. Otherwise, forecast is on track with minimal edits this publish. Expect increasing high clouds tonight, lowering down to 10-15kft tomorrow. Cooler conditions with lighter winds expected tomorrow as well. && .AVIATION...06Z TAFs...VFR conditions expected through the period. Winds will slowly decrease this evening and be less than 10kts at RDM/BDN and YKM/PSC but will remain 10-15kts at PDT/ALW/DLS. Winds will pick up slightly tomorrow afternoon 10-18kts with some higher gusts. Expect increasing high clouds tonight, lowering and becoming sct-bkn 10-15kft tomorrow. && PREV DISCUSSION... /issued 148 PM PDT Tue Aug 11 2020/ SHORT TERM...Tonight through Thursday night...A dry surface cold front is passing over the region this afternoon, with winds increasing across the Cascade gaps. Behind the frontal passage, breezy winds will continue to develop across the lower elevations through the afternoon and evening, with minimum humidities in the low to mid teens. Fire weather warnings have been issued for this afternoon and evening for areas covering the Columbia Basin/Gorge, Yakima valley, and portions of central OR for the breezy conditions and low humidities. Breezy conditions will subside late this evening across the forecast area, with cooler air filtering into the region behind the frontal passage. Tomorrow, region will be under a dry and cool west to northwest flow aloft, with temperatures struggling to get into the lower 80s for most of the forecast area. Diurnal breezy winds will develop across the Cascade gaps in the afternoon, though these winds will be much weaker compared to today. Thursday, much of the same with a dry northwest flow aloft, temperatures warming a few degrees but still below seasonable averages, and afternoon breezy conditions developing in the Cascade gaps. Skies will be fairly clear through the short term forecast period, with increasing mid to high level clouds associated with the frontal passage this evening into tomorrow. Lawhorn/82 LONG TERM...Friday through Tuesday...Period begins with slight ridging encroaching from the west as our trough continues to move well east of the region. This commences a warming period for late week that sends us from seasonably warm to unseasonably hot, especially as the ridging and high pressure pattern is reinforced from the south as a 4 corners ridge takes shape by the end of the weekend. This stronger ridge to our south with ridge axis extending through western US and Canada will present a few concerns for the weekend/early week period. One concern will be the heat itself with large portions of the Columbia Basin, Yakima Valley, and low elevation Blue Mtn foothills experiencing triple digits on Sunday and Monday afternoons. Another concern will be for new fire starts as RHs will be critical during this hot period. Though winds in general appear light and fire weather highlights are not guaranteed, still expecting some breeziness as the atmosphere mixes to great depth each afternoon. A final concern involves storms and their relation to fire weather concerns through the period. Closed off and deep ridging pattern to our south impinging on established N Pacific trough will create deep layer SW/SSW flow aloft and this SW flow may advect enough moisture into the region for afternoon convective initiation. A very slight chance was noticed on Sunday, mainly focusing around 3 Sisters mountains but Monday may hold the potential for greater coverage of isolated storms from central Oregon NE through Wallowa county and lingering showers into Tue for far NE Oregon. A bit early to conjecture beyond stating the possibility though as model spread for moisture and instability remains large. Mid next week, models are split over if residual ridging remains or if a trough approaches close enough to lend winds and higher RHs to next work week. Clark/76 FIRE WEATHER...Red Flag warnings will be in effect from 2pm to 10pm today for fire weather zones WA/OR639, OR640, WA/OR641, and WA675 which covers the Yakima Valley, Lower Columbia Basin, eastern Columbia River Gorge, and central Oregon. The warnings are in effect for low humidities and winds this afternoon and evening. Afternoon RHs are expected to bottom out to between 10 to 20 pct this afternoon, with winds of at least 10 to 20 mph and gusts up to 30 mph possible. Fair to good RH recovery is expected overnight with winds decreasing through the evening. No other critical fire weather concerns are expected until late in the weekend, but RHs will continue to be near critical across the forecast area with non critical diurnal winds in the afternoon each day. Lawhorn/82 && .PRELIMINARY POINT TEMPS/POPS... PDT 56 77 50 81 / 0 10 0 0 ALW 57 78 51 83 / 0 10 0 0 PSC 59 80 53 85 / 0 0 0 0 YKM 56 80 50 83 / 0 0 0 0 HRI 59 81 51 85 / 0 0 0 0 ELN 54 75 52 79 / 0 0 0 0 RDM 48 78 42 83 / 0 0 0 0 LGD 54 74 50 80 / 0 10 0 0 GCD 53 78 49 85 / 0 10 0 0 DLS 61 79 57 84 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && 84/82/76/82/84 UPDATE: 84 SHORT: 82 LONG: 76 FIRE: 82 AVIATION: 84
The national radar mosaic for the moment the first event began.
2 wildfire. Local standard time, as filed.
The Mosier Creek Fire was a human caused timber fire that burned approximately 1000 acres and destroyed 8 residences and 24 other structures. Over 650 structures were threatened during the course of the fire and there were numerous evacuations.
Narrative was pulled from InciWEB site. Lightning sparked the Lionshead Fire, which began August 16, 2020, in Lionshead Canyon on the Confederated Tribes of Warm Springs Reservation approximately 14 miles west of the Warm Springs community. An historic windstorm arrived in the area on Monday, September 7, rapidly spreading the fire west onto the Willamette, Deschutes and Mt. Hood National Forests. The Lionshead Fire has heavily impacted several communities in the Santiam drainage and Breitenbush area, including the loss of 264 resident homes in Detroit. Highly valued natural and cultural resources were also threatened.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2020Every state in 2020This day in weather historyWarnings in Oregon, August 2020
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: 903109, 915320.