Upwelling causes major temperature shift in Lake Michigan waters

·2 min read

WEST MICHIGAN — There was a classic case of upwelling along the east shore of Lake Michigan from Thursday to Friday.

Water temperatures along the lakeshore plummeted, changing up to 25 degrees. At Grand Haven State Park, the water temperature on Thursday was a pleasant 70 degrees. Just 24 hours later, it had fallen to 45 – a drop of 25 degrees.

Lake Michigan water temperatures dropped significantly from Thursday to Friday.
Lake Michigan water temperatures dropped significantly from Thursday to Friday.

Water that cold can be dangerous, and you might not know the water is that cold. It can be tempting to jump off a pier or jump from a boat. If you jump into water that cold, it’s quite a shock to your body. It’s also easy to get hypothermia.

Upwelling occurs when an offshore wind blows the surface water away from the nearshore area, allowing colder water to rise from the bottom of the lake to the surface. This process can happen quickly. Even after a warmer than average summer in mid August, we can see 45-degree water come to shoreline areas.

The water will warm up again when the wind goes west and brings back the warmer surface water, though it’ll be tough to recover back to the mid 70s.

Upwelling can be good for Lake Michigan fishing. The cold water can bring the fish back to the shore.

The high temperature Saturday was 62 degrees. The last time West Michigan had a day with a high temperature of 62 was May 23. Saturday was the coolest high temperature in August since 2015.

This article originally appeared on The Holland Sentinel: Water temperatures drop significantly in Lake Michigan