The first day of summer in Lake Tahoe began under blue skies, but the sunny Saturday suddenly turned dark when a thunderstorm whipped up strong winds and waves of 6 to 8 feet high. At least six people died when a boat capsized near D.L. Bliss State Park around 3 p.m. … Gusts up to 45 mph were measured by a NASA-maintained buoy in the middle of the lake when the cold front hit. It’s likely that stronger winds materialized over a smaller portion of the lake in a phenomenon known as a downburst. Downbursts are caused by rain-cooled air that falls out of a cloud into a drier environment below, often accelerating as it reaches the ground. Once the downdraft reaches the ground, winds spread out in all directions, like water out of a faucet hitting a sink. Weather models estimated favorable conditions for downburst winds over Lake Tahoe on Saturday afternoon, with a mix of dry and moist air amid an unstable atmosphere.

Other Tahoe storm news:

• KRNV (Reno, Nev.): Severe weather capsizes boats at Lake Tahoe prompting oil spill concerns
• FOX Weather: 6 dead, 2 missing after boat capsizes on Lake Tahoe amid large swells, high winds
• KCRA (Sacramento, Calif.): Video: Boats rocked by thunderstorm in South Lake Tahoe