Wednesday December 28, 2022
Washington Post —
The West Coast, ordinarily known for being parched and drought-stricken, is facing a barrage of atmospheric rivers — plumes of deep tropical moisture known for bringing heavy rain and snow. Parts of coastal California, including the Bay Area, are under flood watches, initial signs from the first of several atmospheric rivers set to drench the West in the days ahead.
Weather alerts — for heavy rain in the lowlands, and snow and wind in the mountains — blanket most of central and Northern California. Coastal and central Oregon and Washington are largely under flood watches and high wind warnings, with winter storm warnings in the Cascades and Columbia River Basin.
Atmospheric rivers are ranked on a 1-through-5 scale based on how much moisture they transport from the tropics to the mid-latitudes. The Center for Western Weather and Water Extremes has ranked the ongoing atmospheric river event as a Level 4 out of 5 — that corresponds to “extreme” moisture transport.
The atmospheric river could carry more than 220 million pounds of water through the skies over the Pacific Coast every second — providing copious fuel for downpours.