NOAA Sees West Coast Marine Heatwave Expanding Across 1,000s of Miles as El Niño Odds Top Two-Thirds
Updated
Updated · The Guardian · May 22
NOAA Sees West Coast Marine Heatwave Expanding Across 1,000s of Miles as El Niño Odds Top Two-Thirds
2 articles · Updated · The Guardian · May 22
Summary
NOAA’s latest projections show the vast warm-water mass off the US West Coast will expand and intensify in coming months, reversing hopes from early April that the event might fade.
The heatwave has persisted since peaking in September 2025 and still spans thousands of miles from California to beyond Hawaii, with scientists warning it is already amplifying land heat, drought and weather extremes.
March offered an early signal: temperatures ran more than 30F above normal in parts of Minnesota, Colorado and Idaho, while more than one-third of US weather stations set March records, according to Berkeley Earth.
Across the West, snowpack had completely melted by mid-May in many higher-elevation areas of Oregon, California and Colorado, raising concerns over water supplies, dry thunderstorms and a severe wildfire season.
Marine scientists also fear a replay of the 2014-16 Blob, with salmon, krill, seabirds and other species at risk as subtropical animals shift north; NOAA says the chance of a strong or extreme El Niño later this year is now above two in three.
This record heatwave is here. What happens when it merges with a powerful El Niño later this year?
As Pacific ecosystems unravel, which US industries face the most immediate threat of collapse?
With oceans fueling 'humid heat' and stronger storms, are coastal cities prepared for this new reality?
Dual Climate Extremes in 2026: West Coast Marine Heatwave and El Niño Drive Uncharted Risks and Policy Challenges
Overview
The West Coast of North America is facing a complex climate scenario, with a massive marine heatwave persisting alongside a rapidly developing El Niño. This dual threat creates unique challenges, as the interaction between the heatwave and El Niño could lead to significant and possibly unprecedented impacts on weather patterns and marine ecosystems. The marine heatwave has reached extreme levels, with ocean temperatures surging to record warmth, and is not expected to dissipate quickly. As both phenomena intensify, their combined effects may result in prolonged and unpredictable changes for the region.