Los Angeles has been getting so much rain lately because a series of strong Pacific storm systems, boosted by “atmospheric rivers,” are repeatedly funneling deep tropical moisture into Southern California on already saturated ground. A longer-term backdrop of climate change is also sharpening these swings between drought and deluge, a pattern scientists now call “hydroclimate whiplash.”

Quick Scoop

  • A parade of Pacific storms has targeted California since Christmas week, bringing several inches of rain to the L.A. Basin and much higher totals in nearby mountains.
  • Many of these storms are tied to atmospheric rivers, long, narrow plumes of very moist air that dramatically increase rainfall when they hit the coast and rise over local terrain.
  • Soils around L.A. are already water‑logged from the wettest or near‑wettest Christmas period on record in some spots, so even “moderate” new storms quickly translate into flooding, mudslides, and debris flows.

What’s happening over LA right now?

  • Forecasts around New Year’s call for yet another low‑pressure system moving in, with 1–2 inches of rain possible in coastal and valley areas like downtown L.A., and 2–4 inches in foothills and mountains.
  • The heaviest rain is expected in one or two main waves from New Year’s Eve into New Year’s Day, with additional lighter rain possible afterward, keeping conditions soggy and unstable in steep terrain.

The role of atmospheric rivers

  • Atmospheric rivers act like fire hoses in the sky, transporting huge amounts of subtropical Pacific moisture straight into California, where it condenses and falls as very heavy rain and high‑elevation snow.
  • When several of these moisture plumes line up over days to weeks—as they have this holiday season—they can deliver a month or more of typical L.A. rain in less than a week.

Climate change and “too much rain”

  • Scientists point to a growing “drought‑to‑deluge” pattern in California: years or months of intense dryness followed by very wet storms that break records, like this Christmas in Southern California.
  • As oceans and the atmosphere warm, they can hold more water vapor, which tends to supercharge the strongest storms and make both heavy rainfall events and wildfire‑friendly dry spells more extreme.

What this means for you in LA

  • Short term, expect continued periods of rain, localized flooding, slick roads, and elevated risk of mudslides or debris flows in burn areas and along steep hillsides; heed local watches and warnings.
  • Longer term, experts warn that these intense wet episodes are likely to keep showing up in between dry, high‑fire‑risk years, so L.A. will need stronger drainage, infrastructure, and preparedness to handle the swings.

Information gathered from public forums or data available on the internet and portrayed here.