The Warm Blob Returns

It started, as these things do, with a number that looked slightly wrong. Sea-surface temperatures across a wide stretch of the northeast Pacific have been running two to three degrees above normal for weeks — a quiet anomaly that ocean watchers have learned to take very seriously.

We have seen this before. From 2014 to 2016, a persistent mass of warm water nicknamed "the Blob" settled off the West Coast and refused to leave. It was not dramatic to look at. It was, in its effects, one of the most consequential ocean events in recent memory.

What the last one did

Warm water holds fewer nutrients, and the food web noticed immediately. Plankton thinned. Forage fish moved or died. Seabirds washed ashore by the tens of thousands, and sea lions hauled out hungry. Toxic algal blooms shut down fisheries up and down the coast. On land, the warm offshore water nudged weather patterns enough to deepen drought in some regions.

The Blob was a reminder that the ocean does not need to boil to break a food web. A few degrees, held long enough, is plenty.

What to watch this time

The current anomaly is younger and its future is genuinely uncertain. Marine heatwaves can dissipate in a single stormy season if the winds return and stir cold water back to the surface. They can also lock in, reinforced by a calm atmosphere that lets the warmth sit undisturbed.

Three things are worth keeping an eye on: the strength of the coastal upwelling winds, the persistence of high-pressure ridges over the region, and the first signs of stress in the food web — the seabirds and forage fish that tend to report trouble before the satellites can confirm it. If you want the background on why those winds matter so much, the earlier post on reading the currents lays it out.