meteorologist have described late deluge in California with a captivatingweatherbuzzword : atmospheric river . It does n’t just sound scary — these typewriter ribbon of tropical moisture can actually make terrific floods , mudslides , and damage to route and home .
An atmospherical river is a minute ring of tender precipitation that can span chiliad of miles in distance . They occur from the tropical zone to the mid - latitudes . atmospherical rivers are n’t existent river , of course , but it ’s a jolly honest description of a feature that resembles a river on satellite imagery and can fetch flood of weewee to unlucky communities as the system comes ashore .
These rivers are the result of sprawling low - pressing system that mold just far enough south that their counter - clockwise circulation scoop upwatervapor from the tropics and transports it northwards . The storms that cause atmospheric river to form in the first place are usually able to generate enough up lift to make hurriedness . spate can play a role — they’re very effective at wringing wet out of the atmosphere as wind travels up the side of their terrain . Whether it ’s rain or snow , any hastiness that forms within that stripe of elevated moisture level can be quite heavy , producing extortionate rain sum and many metrical foot of snow in extreme cases .
What Is the “Pineapple Express”?
California has a reputation for unagitated , sunny weather , but the state never really has it easy when it comes to dealing with nature ’s pettishness fit . Within the past X , the Department of State was mire in a devastating drought that wasfinally brokenin 2017 as one storm after another thunder in from the Pacific and drenched the state with unmanageable amounts of heavy rainwater . The drive effect that break each tempest its volume was an atmospheric river . Without it , there would n’t have been much wet for the storm system to figure out with .
An atmospheric river that affects the West Coast — and California in especial — is normally dub aPineapple Expresssince the source of the tropical moisture is the area around Hawaii . atmospherical rivers without a cool nickname are also coarse over the easterly half of the United States during the warm season . Many of the major flash floods that fall out in the easterly U.S. during the summertime months are the resultant of intensethunderstormstapping into the bounteous moisture present in an atmospherical river flowing over the neighborhood .
Allweatheris the result ofnaturetrying to poise out inequality , and atmospherical river , just like every other weather consideration , serve this purpose . Wind blows from areas of high air pressure to areas of low insistency in an attempt to wipe out the inequality of more air molecules over one spot than another . Thejet streamis the lineal result of sharp temperature differences between the tropical zone and thepoles . Hurricanesexist to send heat from the tropics to the poles . atmospherical river live to take wet out of the tropical zone and spread it around the man .
Though atmospheric river seem difficult to enjoy , we ’d be in some moderately bountiful fuss without them . In 1998 , a study by MIT scientist report that 90 pct of all the moisture transfer between the tropics and the residual of the world each yr occurs within these minute band .
A adaptation of this story was published in 2017 ; it has been updated for 2024 .
