Thunderstorm Wind — Bonner, Idaho

2014-08-02 · near Outlet Bay, Bonner, Idaho

Event narrative

Widespread wind damage was observed across the cities of Priest Lake, Sandpoint, Ponderay, Kootenai, Oden, and Lake Pend Oreille. Hundreds of trees ranging from eight to twenty two inches in diameter were snapped or downed. Some trees landed on homes, others took out miles of power lines and poles. At one point after the storm, all of Sandpoint, Idaho was without power. A spotter in Clark Fork stated fifteen foot trees were almost touching the ground while sixty foot trees were bending at 45 degree angles. The most widespread damage was along the Highway 200 corridor between Hope and Sandpoint. The Elk Golf Course in this corridor lost thirteen trees. The Sandpoint AWOS, also in this area, measured sustained winds of 40 mph with gusts to 56 mph before the power outage. A roof of a storage shed was blown off in downtown Sandpoint. Numerous boats and docks on Lake Pend Oreille were damaged from waves that ranged between three to six feet. Significant tree damage was observed on the south side of the lake in Bottle Bay between the 3800th and 5016th blocks. All trees were leaning to the east southeast. Residents interviewed during a storm survey mentioned the winds lasted roughly 40 minutes.

Wider weather episode

A strong upper-level ridge during the end of July and beginning August helped fuel a moist and unstable air mass over the region. The ridge broke down on the 1st of August and was overrun by two weak midlevel impulses on August 2nd. As the second impulse passed over Northeastern Washington and Northern Idaho strong storms developed. Meanwhile, dewpoint depressions over Northern Idaho had spread between 40 and 50 degrees Fahrenheit. The rain and hail cooled outflow winds from storms over Northeastern Washington and North Idaho put out damaging outflow winds which moved northwest to southeast and gained momentum while tracking off the Selkirk Mountain Range. Winds ranging between 50 and 70 miles per hour blew through Priest Lake, Sandpoint, Lake Pend Oreille, and Prichard. Meanwhile, isolated thunderstorms were developing along a decaying outflow boundary tracking west to east across the Washington, Idaho border, each producing local tree damage. Priest Lake, Sandpoint, and communities surrounding Lake Pend Oreille were the hardest hit areas.

View location on OpenStreetMap → (48.3728, -117.0360)

Source: NOAA Storm Events Database, event_id 534581. Narrative written by the NWS forecast office that issued the report.