May 10th - May 18th: Temperatures across the area were abnormally warm from May 6th through May 11th with high temperatures in the valleys up into the upper 70s to mid 80s. This was caused by a strong blocking high pressure system that established itself over the region.
Every event with a place to put it. 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 OTX wrote it up.
May 10th - May 18th: Temperatures across the area were abnormally warm from May 6th through May 11th with high temperatures in the valleys up into the upper 70s to mid 80s. This was caused by a strong blocking high pressure system that established itself over the region. The warm temperatures melted high level snow pack across British Columbia, which resulted in substantial rises to the Okanogan River through the middle portions of May. Flooding was observed along the river from Oroville to Okanogan in the Okanogan Valley.
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 May 9, 9:46 PM PST, 2 hours 14 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 1046 PM PDT Thu May 9 2013 .SYNOPSIS... Unseasonably warm and dry conditions will continue for the Inland Northwest through Saturday. The warm temperatures will lead to rapid snow melt and rising river levels, particularly across the northern mountains. Isolated thunderstorms are possible across the mountains Friday and Saturday, mainly over North Idaho. A cold front arriving on Sunday will bring a better chance of showers and more spring like temperatures into early next week. && .DISCUSSION... Strong high pressure will remain in place tonight promoting clear skies. Convection earlier clipped the Central Panhandle Mountains south of Lookout Pass but this activity has shifted well south of the area. For Friday high pressure will remain firmly in place for another day of high temperatures around 20 degrees above normal. Model show some instability, but most of this being capped. With very little activity today, the same scenario will likely repeat itself tomorrow. Thus...made some minor adjustments to the thunderstorms tomorrow...with slight chance wording after 2 pm confined mainly to the higher peaks of the North Idaho Panhandle. JW && .AVIATION... 06Z TAFS: Generally clear skies expected at the TAF sites through Friday afternoon...with some increase in mid and high level clouds Friday night. The atmosphere will again destabilize Friday afternoon with cumulus build ups over the mountains...along with a slight chance of thunderstorms after 21z mainly for the Idaho Panhandle. JW && .PRELIMINARY POINT TEMPS/POPS... Spokane 55 84 55 84 56 83 / 0 0 0 0 10 40 Coeur d'Alene 51 83 52 82 54 81 / 0 0 0 0 10 40 Pullman 49 82 51 82 53 81 / 0 0 0 0 10 30 Lewiston 56 87 57 88 58 87 / 0 0 0 0 10 20 Colville 49 89 49 89 51 84 / 0 0 10 0 10 40 Sandpoint 45 81 47 81 49 81 / 0 10 10 10 10 50 Kellogg 51 81 49 77 51 78 / 0 10 10 10 10 50 Moses Lake 54 92 55 93 59 86 / 0 0 0 0 0 30 Wenatchee 57 90 57 88 59 80 / 0 0 0 0 10 20 Omak 52 90 51 89 52 83 / 0 0 0 0 10 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SPOKANE WA 526 PM PDT THU MAY 9 2013 IDZ001>004-026-027-WAZ031>038-110030- NORTHERN PANHANDLE-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- NORTHEAST MOUNTAINS-OKANOGAN HIGHLANDS- 526 PM PDT THU MAY 9 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH IDAHO... NORTH CENTRAL IDAHO...EAST CENTRAL WASHINGTON...NORTH CENTRAL WASHINGTON...NORTHEAST WASHINGTON AND SOUTHEAST WASHINGTON. .DAY ONE...TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THE THREAT OF ISOLATED TO SCATTERED THUNDERSTORMS COMES ON SUNDAY AND MONDAY WITH A COLD FRONT. A FEW STRONG STORMS ARE POSSIBLE AND MAY BE CAPABLE OF BRIEF HEAVY DOWNPOURS...SMALL HAIL...GUSTY WINDS AND OCCASIONAL LIGHTNING. THE HIGHEST CHANCES COME IN THE LATER AFTERNOON AND EVENING HOURS. CHANCES LOOKS HIGHEST ACROSS IDAHO AND THE NORTHEAST MOUNTAINS SOUTH INTO THE PALOUSE AND BLUE MOUNTAINS. WAZ041>044-110030- WENATCHEE AREA-EAST SLOPES NORTHERN CASCADES-OKANOGAN VALLEY- WATERVILLE PLATEAU- 526 PM PDT THU MAY 9 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL WASHINGTON AND NORTH CENTRAL WASHINGTON. .DAY ONE...TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE MONDAY AFTERNOON AND EVENING. A FEW STORMS MAY BECOME STRONG WITH THE POTENTIAL FOR BRIEF DOWNPOURS...SMALL HAIL...GUSTY WINDS AND ISOLATED LIGHTNING STRIKES.
The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
A National Weather Service employee surveyed the Okanogan River near Tonasket and found pasture fields, and, to a lesser extent, agricultural fields flooded during peak flow.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2013Every state in 2013This day in weather historyWarnings in Washington, May 2013
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: 444492.