About five years ago “the Blob” of warm ocean water disrupted the West Coast marine ecosystem and depressed salmon returns. Now, a new expanse of unusually warm water has quickly grown in much the same way, in the same area, to almost the same size.
The warm expanse building off the West Coast stretches roughly from Alaska south to California. It ranks as the second largest marine heatwave in terms of area in the northern Pacific Ocean in the last 40 years, after "the Blob."
“It’s on a trajectory to be as strong as the prior event,” said Andrew Leising, a research scientist at NOAA Fisheries’ Southwest Fisheries Science Center in La Jolla, California. He developed a system for tracking and measuring heatwaves in the Pacific Ocean using satellite data. “Already, on its own, it is one of the most significant events that we’ve seen.”
Cold water welling up from ocean depths along the coast has so far held the warm expanse offshore, he said. However, the upwelling, driven by coastal winds, usually wanes in the fall. The heatwave could then move onshore and affect coastal temperatures, he said. This already appears to have happened along the coast of Washington.
The new marine heatwave off the West Coast stands out in this map of sea surface temperature anomalies, with darker red denoting temperatures farther above average. The highest temperatures shown are more than 5 degrees Fahrenheit above average. Image from NOAA Coral Reef Watch, which corrects effectively for cloud cover.
NOAA Fisheries is focusing additional monitoring on the new heatwave, designated the Northeast Pacific Marine Heatwave of 2019. NOAA Fisheries’ Southwest and Northwest Fisheries Science Centers will provide fisheries managers and others with information on how the unusually warm conditions could affect the marine ecosystem and fish stocks.
“We learned with ‘the Blob’ and similar events worldwide that what used to be unexpected is becoming more common,” said Cisco Werner, NOAA Fisheries Director of Scientific Programs and Chief Science Advisor. “We will continue to inform the public about how the heatwave is evolving, and what we might anticipate based on experience.”
The new heatwave resembles the early stages of “the Blob.” This previous marine heat wave peaked through 2014 and 2015 with temperatures close to seven degrees Fahrenheit above average.
Blob Could Dissipate Quickly
Like “the Blob,” the new heatwave emerged over the past few months. A ridge of high pressure dampened the winds that otherwise mix and cool the ocean’s surface. The heatwave remains relatively new and is primarily affecting the upper layers of the ocean, it could break up rapidly.
“It looks bad, but it could also go away pretty quickly if the unusually persistent weather patterns that caused it change,” said Nate Mantua, a research scientist at the Southwest Fisheries Science Center.
Current forecasts show the heat wave moderating but continuing for months.
A key question is whether the new heatwave will last long enough to affect the marine ecosystem. Biologists say that its large size means it probably already has. For example, warmer conditions during “the Blob” left lesser-quality food available to young salmon entering the ocean. It also shifted predator distributions in ways that contributed to low returns of salmon.
Shifts in the marine food web during the evolution of the 2014-2015 marine heatwave called, "the Blob," forced sea lion mothers to forage further from their rookeries in the Channel Islands off Southern California. Hungry pups set out on their own, but many became stranded on area beaches.
Other impacts linked to the earlier heatwave include:
The largest harmful algal bloom recorded on the West Coast, which shut down crabbing and clamming for months.
Thousands of young California sea lions stranding on beaches.
Multiple declared fishery disasters.
NOAA Fisheries scientists recently convened a special meeting to discuss the emerging heatwave and how to anticipate and track its effects. They are now reviewing impacts documented during the “the Blob” to compare them against the effects of the emerging heatwave.
“Given the magnitude of what we saw last time, we want to know if this evolves on a similar path,” said Chris Harvey, a research scientist at the Northwest Fisheries Science Center.
Monitoring Framework in Place
NOAA Fisheries’ two West Coast laboratories collaborate on the California Current Integrated Ecosystem Assessment. This is a joint effort to track and interpret environmental change off the West Coast. That provides a framework to monitor shifting conditions, Harvey said.
One challenge will be applying lessons learned from the last heat wave to anticipate and mitigate potential impacts of the new one. For example, the warm water of “the Blob” led humpback and other whales to feed closer to shore. Record numbers became entangled in lines from crab traps and other fishing gear.
In response, fishermen, managers, and others have formed working groups in California, Oregon, and Washington. They hope to find ways of reducing the risk of entanglements.
The marine heatwave that has formed off the West Coast of North America is currently close to the warmest area in the Pacific Ocean. Map shows sea surface temperature anomalies, with darker orange representing temperatures farther above average. Image from NOAA National Environmental Satellite, Data, and Information Service.
Real-time research on environmental changes will give managers the details they need to respond, said Kristen Koch, Director of the Southwest Fisheries Science Center. “This is a time when we all need to know how our marine ecosystem is changing, and what that means for those of us who live along the West Coast.”
The new northeast Pacific heatwave reflects current weather patterns. This includes a band of high pressure stretching north to the Bering Sea and Alaska, which have been unusually warm in recent years, said Nick Bond, a research meteorologist with the Joint Institute for the study of the Atmosphere and Ocean in Seattle, a collaboration between NOAA and the University of Washington.
Scientists monitoring new marine heat wave off B.C. coast similar to 'the Blob'
A new marine heat wave spreading across a portion of the Pacific Ocean off the coast of British Columbia has so far grown into one of the largest of its kind in the last four decades, officials say, second only to the infamous "blob" that disrupted marine life five years ago.
The swath of unusually warm water stretches roughly from Alaska down to California, according to the National Oceanic and Atmospheric Administration (NOAA) in the United States. The marine phenomenon began in the Gulf of Alaska sometime around June 15 and ballooned over the summer.
A marine heat wave happens when sea surface temperatures are higher than normal for at least five consecutive days.
Officials tracking the system said it is already the second-largest experts have seen since 1981 — the first year for which satellite data used to track marine heat waves is available.
"Already, on its own, it is one of the most significant events that we've seen," Andrew Leising, a research scientist at the NOAA's Southwest Fisheries Science Center in La Jolla, Calif., said in a statement Thursday.
Above average water temperature
Leising said this year's heat wave resembles a similar West Coast heat wave that upset marine life in 2014 and 2015. Nicknamed "the Blob," the system, which stretched from Mexico to the Bering Sea, was blamed for warmer weather on land, abysmal feeding conditions for salmon and the sudden deaths of two dozen whales in the Pacific.
The Blob saw temperatures in the water peak at 3.9 C above average. The NOAA said the water this year has already reached temperatures of more than 2.7 C above average off the coast of Washington state.
"It's on a trajectory to be as strong as the prior event," said Leising, who developed a system for tracking and measuring heat waves in the Pacific Ocean using satellite data.
"It's really only time that will tell if this feature is going to persist and then rival [the Blob]."
The NOAA said its staff is monitoring this year's system to see whether it will last long enough to impact the marine ecosystem, though some biologists suggest it already has based on its sheer size.
The agency blamed the recent marine heat wave on a persistent weather pattern that began in June: weaker-than-normal winds and a weaker high-pressure system over the wedge of warm ocean between B.C., Hawaii and Washington state.
Officials say a formal analysis to try to pinpoint the reasons for the unusual weather pattern will take "some months" to complete. During the previous "blob" event, a number of studies suggested long-term ocean warming due to climate change made the heat wave stronger than it otherwise would have been.
Cold water rising along the coast from the ocean depths has held the warmer water offshore thus far, but experts said the chilled surge usually peters out in the fall. The heat wave in the water could move onshore and affect coastal temperatures if that happens, Leising said in the statement.
Officials also noted the marine heat wave is still new enough to break up if the weather shifts.