Month, california has been affected by severe weather, including bomb cyclones and atmospheric rivers. the storms have killed at least 18 people and left tens of thousands of people without power. severe droughts in the west have exacerbated the situation, as the region’s ability to absorb the water has been diminished. forest fires have also destabilised areas, making landslides more likely.
Meteorological plumes of moisture have been affecting california this month, overlapping with other severe weather. the federal government estimates that 50% of california’s annual rain and snowfall comes from atmospheric rivers, one of which is the pineapple express. these rivers can stretch 1,000 miles (1,600km) long and 350 miles wide.
Rivers occur when water evaporates into the air and is carried along by the wind. warm conditions in hawaii help evaporate ocean waters into the atmosphere. winds swiftly carry the vapour, which, if lifted by a front or passing over mountains, condenses and falls as rain or snow. this regular phenomenon has brought torrential rains to california and other parts of the western united states, especially during winter’s cooler months.