La Niña, Atmospheric River, Bomb Cyclone
The SF Bay Area and much of Northern California have been getting soaked with rain this weekend. There are a variety of names used to describe the weather phenomena at play: La Niña, Atmospheric River, and Bomb Cycle. What's in a name?
La Niña: Spanish for "baby girl" this name sounds downright mild. It describes a condition where waters in the tropical Pacific Ocean are warmer than normal. This shifts around the prevailing winds in a way that gives the Pacific Northwest rainier weather and the US Southwest drier weather. Here in the Bay Area our weather can go either way, wetter or drier. La Niña conditions last for a year or longer at a time.
Atmospheric River: This one sounds like it could go either way. Rivers are good, right? But rivers are also dangerous, and can flood. This name describes an atmospheric condition where wind currents carry warm, moist air from the tropics to the West Coast. It lasts for a few days at a time and dumps rain on us. It's also called a Pineapple Express because the weather system comes from Hawaii.
Bomb Cyclone: Okay, I gotta say, nothing sounds good about this name. A cyclone is a violent weather thing like a tornado. And a bomb? Either one on its own is bad; put them together and it's like... I dunno... a sharknado?
So, all three of these are happening at the same time in California right now, bringing us heavy rain and high winds. While we desperately need rain to replenish drought stricken reservoirs and groundwater tables the amount of rain we're getting all at once has oversaturated the ground, causing flash floods and slides. And the wind's a hazard, too.
Near where I live the weather has been relatively mild. We've had 1-2 inches of rain in the past 24 hours plus occasionally gusty winds. Elsewhere in the Bay Area rainfall has been 4 inches, 5 inches, up to 10+ inches in some places. And winds have been fierce enough to topple trees, knock out power lines, and flip over trucks on highways.
Update: I posted an explainer on how atmospheric rivers work.
[This entry was cross-posted from https://canyonwalker.dreamwidth.org/134627.html. Please comment there using OpenID. That's where most of the action is!]
La Niña: Spanish for "baby girl" this name sounds downright mild. It describes a condition where waters in the tropical Pacific Ocean are warmer than normal. This shifts around the prevailing winds in a way that gives the Pacific Northwest rainier weather and the US Southwest drier weather. Here in the Bay Area our weather can go either way, wetter or drier. La Niña conditions last for a year or longer at a time.
Atmospheric River: This one sounds like it could go either way. Rivers are good, right? But rivers are also dangerous, and can flood. This name describes an atmospheric condition where wind currents carry warm, moist air from the tropics to the West Coast. It lasts for a few days at a time and dumps rain on us. It's also called a Pineapple Express because the weather system comes from Hawaii.
Bomb Cyclone: Okay, I gotta say, nothing sounds good about this name. A cyclone is a violent weather thing like a tornado. And a bomb? Either one on its own is bad; put them together and it's like... I dunno... a sharknado?
So, all three of these are happening at the same time in California right now, bringing us heavy rain and high winds. While we desperately need rain to replenish drought stricken reservoirs and groundwater tables the amount of rain we're getting all at once has oversaturated the ground, causing flash floods and slides. And the wind's a hazard, too.
Near where I live the weather has been relatively mild. We've had 1-2 inches of rain in the past 24 hours plus occasionally gusty winds. Elsewhere in the Bay Area rainfall has been 4 inches, 5 inches, up to 10+ inches in some places. And winds have been fierce enough to topple trees, knock out power lines, and flip over trucks on highways.
Update: I posted an explainer on how atmospheric rivers work.
[This entry was cross-posted from https://canyonwalker.dreamwidth.org/134627.html. Please comment there using OpenID. That's where most of the action is!]