A “once in a decade” bomb cyclone pummeled the Pacific Northwest on early Wednesday, with southern Canada and Washington, Oregon and California experiencing wind speeds as high as 101 mph (163 km/hr), torrential rain and heavy mountain snow.
At least one person is confirmed to have died from the storm — a woman in her 50s who was killed after a large tree fell on her homeless encampment — while hundreds of thousands of others in the affected area are without power.
The so-called “bomb cyclone” is a previously-rare superstorm that often occurs during winter after a rapid deepening in low pressure within a specific area. After this process (officially known as explosive cyclogenesis) takes place, the resulting bomb cyclone has been known to produce winds of 74 to 95 mph (120 to 155 km/h), on par with the most extreme hurricanes studied on the Saffir–Simpson scale.
This particular storm was exacerbated by the fact that it occurred as we enter the La Niña cycle, or a period in the ocean’s natural cycles when temperatures cool in the central and east-central equatorial Pacific region. La Niña seasons typically produce large numbers of atmospheric rivers, or narrow bands of concentrated water vapor in the sky that act like rivers in the sky. Atmospheric rivers are also more likely to occur because of climate change. In addition to fueling Wednesday’s freakish bomb cyclone in the Pacific Northwest, atmospheric rivers were also responsible for a freakish Antarctic heat wave in April. Concordia Station, a French-Italian research institute near the South Pole, recorded temperatures 30° to 40°C above the average, peaking at -9.4°C or 15°F. This was several degrees warmer than the previous all-time high at that station.
