One of the most widespread severe weather events occurred across the Spokane County Warning Area on July 20th.  Several days prior to the day of the event, a deep upper-level low slowly sagged down the Pacific Northwest Coastline.  Southerly flow ahead of the low pumped moist, unstable air into the Inland Northwest.  The combination of afternoon heating and smaller impulses ejecting from the offshore low kept the region very unsettled with several rounds of severe thunderstorms from the 15th through the 19th.  On the morning of the 20th, the remnants of Tropical Storm Fabio became ingested into the southerly flow and transported toward the region.  Meanwhile, a shortwave dropping into the Gulf of Alaska acted to kick the upper-low off the southwestern Oregon Coast inland.  The upper-level wave took on a strong negative tilt, driven northeastward by a 75kt jet streak, crossing through Eastern Washington during the early to late afternoon on July 20th.  The combination of strong dynamic forcing along the shortwave, presence of an abnormally moist, unstable air mass, time of day, highly diffluent flow aloft, and jet streak dynamics led to numerous severe thunderstorms across Eastern Washington.  Severe hail, winds, and flash flooding were observed with storms during the early afternoon but the threat transitioned to severe winds by the mid to late afternoon as storms migrated into the Northeastern Mountains.  These storms blew down hundreds of trees causing one fatality.  Ferry and Okanogan Counties were the hardest hit counties and experienced power outages in some remote communities in excess of one week.  Consequently, state and federal assistance was necessary.  Preliminary damage figures for Ferry County estimated 2.6 million in debris removal, 1.6 million in emergency protective measures, 128 thousand for road and bridge repair, 570 thousand to building and equipment, 3.2 million for utility repair, and 163 thousand for parks and recreation.  7000 people lost power in Ferry County and three major roads were closed for sometime due to downed trees.  These roads included Highway 21, 97, and 155.  Utility companies estimated 200 downed power poles and 40 miles of line needed restoration.  In Okanogan County, estimations of 82 thousand in debris removal, 36 thousand in emergency protective measures, 180 thousand for road and bridge repair, 419 thousand to building and equipment, 364 thousand for utility repair, and 25 thousand for parks and recreation.  Cumulative figures indicated a total of 8.4 million for Ferry and 1.1 million for Okanogan.  Due to the complexity and magnitude of this event, Appendix B was utilized to estimate individual costs for each event.  Cumulative figures listed in the Episode narrative would be more representative of the actual event.  Some reports stated that private weather instruments at residents' houses recorded winds between 80 and 100 mph.

Flash Flood in ASOTIN, WASHINGTON
From 20-JUL-12 11:35:00 to 20-JUL-12 11:50:00 (PST-8)
Location: ANATONE
Flood cause: Heavy Rain
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Park/Forest Service

Park Ranger reported water out of ditches and over roads.  Road damage due to the water.

Flash Flood in GRANT, WASHINGTON
From 20-JUL-12 12:10:00 to 20-JUL-12 12:30:00 (PST-8)
Location: CORFU
Flood cause: Heavy Rain
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A washout occurred along Lower Crab Creek Road.

Flash Flood in OKANOGAN, WASHINGTON
From 20-JUL-12 14:00:00 to 20-JUL-12 14:20:00 (PST-8)
Location: OMAK
Flood cause: Heavy Rain
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Public

City Hall had to be sandbagged due to water flowing into the building.

Flash Flood in OKANOGAN, WASHINGTON
From 20-JUL-12 14:30:00 to 20-JUL-12 14:50:00 (PST-8)
Location: DISAUTEL
Flood cause: Heavy Rain
Property damage: 6.00K
Crop damage: 0.00K
Reported by: Public

Several dirt roads and driveways were washed out along D-Rez Loop Road.  State Route 155 was shut down for a short time at Milepost 59 due to undercutting of the roadway.

Hail in GRANT, WASHINGTON
From 20-JUL-12 12:15:00 to 20-JUL-12 12:20:00 (PST-8)
Location: MAE
Magnitude: 1.25 
Property damage: 1.00K
Crop damage: 5.00K
Reported by: Public

Hail broke one window and caused window trim from five other windows to break off.  The hail also damaged corn and alfalfa fields as well.

Thunderstorm Wind in FERRY, WASHINGTON
From 20-JUL-12 14:42:00 to 20-JUL-12 14:49:00 (PST-8)
Location: KELLER POOLER ARPT
Magnitude: 57.00 EG
Property damage: 0.00K
Crop damage: 2.00K
Reported by: Trained Spotter

Trees and power lines were down on Highway 21.

Thunderstorm Wind in FERRY, WASHINGTON
From 20-JUL-12 15:00:00 to 20-JUL-12 15:05:00 (PST-8)
Location: REPUBLIC
Magnitude: 61.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: COOP Observer

Numerous large trees and power lines were blown down in and around Republic between 4 PM and 430 PM.  Trees fell on a houses and blocked Highway 20 for a period of time.

Thunderstorm Wind in FERRY, WASHINGTON
From 20-JUL-12 15:15:00 to 20-JUL-12 15:20:00 (PST-8)
Location: REPUBLIC
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

A woman was killed by a falling tree while camping along Trout Creek.

Hail in GRANT, WASHINGTON
From 20-JUL-12 12:35:00 to 20-JUL-12 12:40:00 (PST-8)
Location: MAE
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in GRANT, WASHINGTON
From 20-JUL-12 12:50:00 to 20-JUL-12 12:55:00 (PST-8)
Location: (MWH)GRANT CO ARPT M
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in GRANT, WASHINGTON
From 20-JUL-12 13:07:00 to 20-JUL-12 13:12:00 (PST-8)
Location: ADRIAN
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in GARFIELD, WASHINGTON
From 20-JUL-12 13:35:00 to 20-JUL-12 13:40:00 (PST-8)
Location: COLUMBIA CENTER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in GARFIELD, WASHINGTON
From 20-JUL-12 13:35:00 to 20-JUL-12 13:40:00 (PST-8)
Location: COLUMBIA CENTER
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm Wind in GRANT, WASHINGTON
From 20-JUL-12 11:55:00 to 20-JUL-12 12:00:00 (PST-8)
Location: BEVERLY
Magnitude: 57.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Measured at the Vantage Washington DOT sensor.

Thunderstorm Wind in SPOKANE, WASHINGTON
From 20-JUL-12 13:30:00 to 20-JUL-12 13:35:00 (PST-8)
Location: SPOKANE
Magnitude: 43.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Broadcast Media

A large tree branch fell onto two cars near the intersection of Wall and Maxwell Streets.

Thunderstorm Wind in OKANOGAN, WASHINGTON
From 20-JUL-12 14:00:00 to 20-JUL-12 14:05:00 (PST-8)
Location: OMAK
Magnitude: 52.00 EG
Property damage: 1.50K
Crop damage: 0.00K
Reported by: Public

Trees were blown down on West Ridge Drive.

Thunderstorm Wind in GRANT, WASHINGTON
From 20-JUL-12 14:25:00 to 20-JUL-12 14:30:00 (PST-8)
Location: ELECTRIC CITY
Magnitude: 60.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Public

Public reported a few trees completely blown down.  Numerous tree limbs were snapped off trees that remain standing.

Thunderstorm Wind in OKANOGAN, WASHINGTON
From 20-JUL-12 14:30:00 to 20-JUL-12 14:35:00 (PST-8)
Location: NESPELEM
Magnitude: 56.00 EG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Public

Nespelem School reported a downed tree roughly 10 to 12 inches in diameter.   The tree fell on and damaged a dumpster.

Thunderstorm Wind in FERRY, WASHINGTON
From 20-JUL-12 14:30:00 to 20-JUL-12 14:35:00 (PST-8)
Location: KELLER
Magnitude: 56.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law Enforcement reported trees down on Manilla Creek Road.

Thunderstorm Wind in FERRY, WASHINGTON
From 20-JUL-12 14:35:00 to 20-JUL-12 14:40:00 (PST-8)
Location: KELLER
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 2.00K
Reported by: Broadcast Media

Trees were blown down on Silver Creek Road.

Thunderstorm Wind in OKANOGAN, WASHINGTON
From 20-JUL-12 14:40:00 to 20-JUL-12 14:45:00 (PST-8)
Location: NESPELEM
Magnitude: 56.00 EG
Property damage: 8.00K
Crop damage: 0.00K
Reported by: Post Office

The Post Office building sustained roof damage.  Rain entered the office lobby and resulted in minor water damage.  Dime size hail was also reported with the storm.

Thunderstorm Wind in FERRY, WASHINGTON
From 20-JUL-12 14:46:00 to 20-JUL-12 14:51:00 (PST-8)
Location: KELLER POOLER ARPT
Magnitude: 56.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trees and power lines were down on Cache Creek Road.

Thunderstorm Wind in FERRY, WASHINGTON
From 20-JUL-12 15:26:00 to 20-JUL-12 15:31:00 (PST-8)
Location: MATNEYS SPUR
Magnitude: 56.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Numerous trees were blown down on State Route 20 at Sherman Pass.  The highway was temporarily closed.

Thunderstorm Wind in STEVENS, WASHINGTON
From 20-JUL-12 15:26:00 to 20-JUL-12 15:31:00 (PST-8)
Location: MARCUS
Magnitude: 56.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm winds knocked down trees and power lines temporarily blocking Highway 395.

Thunderstorm Wind in FERRY, WASHINGTON
From 20-JUL-12 15:30:00 to 20-JUL-12 15:35:00 (PST-8)
Location: BOYDS
Magnitude: 56.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several trees were blown down from thunderstorm winds.

Thunderstorm Wind in OKANOGAN, WASHINGTON
From 20-JUL-12 15:45:00 to 20-JUL-12 15:55:00 (PST-8)
Location: NIGHTHAWK
Magnitude: 57.00 EG
Property damage: 120.00K
Crop damage: 0.00K
Reported by: NWS Employee

A tree was blown down and landed on a house.  Several other trees were blown down at the adjacent campground.

Debris Flow in CHELAN, WASHINGTON
From 20-JUL-12 13:15:00 to 20-JUL-12 13:35:00 (PST-8)
Location: STEHEKIN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in ADAMS, WASHINGTON
From 20-JUL-12 12:15:00 to 20-JUL-12 12:22:00 (PST-8)
Location: MOODY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Caller reported quarter size hail and very heavy rain which resulted in localized urban flooding.

Thunderstorm Wind in FERRY, WASHINGTON
From 20-JUL-12 14:30:00 to 20-JUL-12 14:35:00 (PST-8)
Location: KELLER
Magnitude: 61.00 EG
Property damage: 400.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hundreds of trees were blown down in the area.  Multiple trees landed on houses.

Thunderstorm Wind in FERRY, WASHINGTON
From 20-JUL-12 14:30:00 to 20-JUL-12 14:35:00 (PST-8)
Location: KELLER
Magnitude: 61.00 EG
Property damage: 500.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Numerous trees were blown down in the town of Keller.  Several trees fell onto houses causing significant damage.

Thunderstorm Wind in FERRY, WASHINGTON
From 20-JUL-12 15:32:00 to 20-JUL-12 15:37:00 (PST-8)
Location: MALO
Magnitude: 56.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds blew down a 50 year old pine tree.  Two to four foot waves were observed on Lake Curlew.

Thunderstorm Wind in OKANOGAN, WASHINGTON
From 20-JUL-12 14:30:00 to 20-JUL-12 14:35:00 (PST-8)
Location: DISAUTEL
Magnitude: 56.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Department of Highways

One large tree and some smaller trees were blown down onto Highway 155.