\u201cNEP25A gained much of its size when a low-pressure system crossing the Gulf of Alaska reversed coastal winds that had helped cool the ocean surface. The heatwave grew and approached the West Coast approximately one month ahead of other large heatwaves in recent years,\u201d NOAA IEA notes.<\/p>\n
NEP25A is part of a much larger ongoing marine heat wave system stretching across the North Pacific<\/a>, from the waters off Japan to North America\u2019s west coast.<\/p>\n Several recent<\/a> studies<\/a> attribute the rising marine heat waves in the Northeast and North Pacific to climate change<\/a>.<\/p>\n \u201cFive of the six largest marine heat waves in the Northeast Pacific have all occurred in the last six years,\u201d Free said. \u201cThis trend in record breaking heat is alarming because of its impacts on ocean ecosystems and economies.\u201d<\/p>\n The 2013-2016 Northeast Pacific heat wave, for instance, led to the collapse of kelp forests<\/a>, mass deaths of seabirds<\/a> and sea lions washing ashore<\/a>, harmful algal blooms, and the disruption of entire marine food webs<\/a>. Fisheries like those of the Pacific sardine also suffered, Free said.<\/p>\n The current blob, NEP25A, has also \u201cbeen accompanied by reports of warmer-water species such as marlin and tuna to the north of their typical range, and signs of harmful algal blooms that can be fueled by warmer waters along the Oregon Coast,\u201d NOAA Fisheries said in a statement to Mongabay. \u201cIf the marine heatwave grows and persists, it may further affect the large California Current Ecosystem through shifts in marine life and changes in the food web, for instance.\u201d<\/p>\n However, \u201cNOAA\u2019s latest forecasts predict that marine heatwave conditions will ease near the West Coast as we move into winter, though they are likely to persist farther offshore,\u201d the statement added.<\/p>\n Banner image: North Pacific Ocean temperature anomalies on September 28, 2025. Positive values mean areas warmer than average; negative values means cooler than average. Image via NOAA Coral Reef Watch.<\/p>\n <\/p>\n