Winter Storm — San Juan, Washington

2021-02-13 · San Juan, Washington

Event narrative

A significant winter storm brought heavy snowfall to the San Juan Islands late in the evening and into the overnight period from February 12 to February 13. Local CoCoRaHs reports around daybreak on February 13 ranged from generally 5-10 inches of snow through that short time period.

Wider weather episode

A significant snowstorm impacted the lowlands of Washington beginning during the evening hours of February 12 and continuing through the morning of February 13. Strong Fraser outflow was responsible for the advection of much colder air west of the Cascade Crest. As this cold air entrenched the Western Washington lowlands, a strong storm system was approaching from off the Pacific, bringing with it sufficient moisture towards the area. The low made landfall near the mouth of the Columbia River during the early morning hours of the 13th, which was the prime location to allow for significant snowfall over Western Washington. Heavy snowfall accumulated quickly overnight and continued through the morning of the 13th before tapering during the afternoon and evening.

Source: NOAA Storm Events Database, event_id 945669. Narrative written by the NWS forecast office that issued the report.