Memorial Day weekend usually means a parade of boats on the Lower St. Croix River. This year it'll be a slow-motion parade, though.

All the rain over the past few weeks has pushed the St. Croix's water level so high that the stretch from Taylors Falls to Prescott – 52 miles of river – is now a no wake zone.

What's that mean? It means slooow – the slowest possible speed that still lets you steer the boat and definitely nothing over five miles an hour, the Minnesota DNR says.

Why slow down in high water?

When the water is unusually high, the river is lapping against parts of the bank it doesn't normally reach. So if a boat is going fast enough to leave a wake, waves are more likely to cause erosion or even property damage.

The DNR says it's also safer for boaters to slow down because high water is more likely to have floating debris just below the surface. For more than 30 years they've been enforcing the no wake rule whenever the St. Croix gets to 683 feet above sea level.

It hit that level Wednesday and forecasters don't expect it to drop much over the next several days. The chart below is from the National Oceanic and Atmospheric Administration. You can find their latest St. Croix info here.

The no wake restriction will last until the river level at Stillwater drops below 683, whenever that is. Washington County Sheriff's office is telling boaters the water will stay high at least through Sunday. They say they've told marinas about the no wake rule and posted signs along the river.

You can get a ticket and a fine for breaking the rule.

It's been a soggy May

The high water is not surprising when you look at how much rain has fallen in the area lately. Climate numbers show the average rainfall for the Twin Cities area in the whole month of May is 3.3 inches.

But some of the areas that drain into the St. Croix got more than that in a week.

The no wake zone is from Taylors Falls to Prescott, Wisconsin, where the St. Croix empties into the Mississippi River. Areas above that have lots of water too, though. The National Park Service monitors the river at seven places upstream from Taylors Falls and all of them list water levels as high or very high.