A new state law requiring carbon monoxide detectors in some boats in Minnesota takes effect this week.

Starting Tuesday, all boats that have an "enclosed accommodation area" — sleeping areas, galleys with sinks, toilet compartments — must have a marine-certified carbon monoxide detector. An estimated 8,000 boats in Minnesota are affected by the measure.

Sophia's Law, named for Edina 7-year-old Sophia Baechler, who died in 2015 on Lake Minnetonka when carbon monoxide leaked from a hole in the boat's exhaust pipe, also requires all motorboats with "an enclosed occupancy space" — smaller areas that a person might enter — to have three carbon monoxide poisoning warning stickers instead of a detector.

Minnesota, which ranks No. 1 in the nation for most boats per capita, has more than 540,000 motorboats, and the Department of Natural Resources estimates about 45,000 will need the free stickers.

The law, the most stringent of its kind in the nation, was supposed to take effect last year but was delayed due to issues about the availability of the detectors.

Carbon monoxide poisoning occurs when the gas builds up from an idling motor, generator or faulty motor exhaust system. The toxic gas is odorless and invisible. Symptoms include headaches, dizziness, weakness, nausea, vomiting, chest pain and confusion. For more information, go to dnr.state.mn.us.

KELLY SMITH

New Minnesota law requires carbon monoxide detectors like this in enclosed cabin boats. ] GLEN STUBBE • glen.stubbe@startribune.com Friday, May 26, 2017 Memorial Day weekend kicks off the unofficial start to the boating season in Minnesota. Boaters this year will continue to see ramped up efforts statewide to enforce safe boating and inspections aimed at slowing the spread of invasive species from lake to lake

Red River Valley

Gradual spring melt lowers valley's flood risk

The coming of April often means a flood fight in the cities along the Red River of the North. But not this year.

Warm days coupled with below-freezing nighttime temperatures led to a gradual snow melt throughout the valley, making for a rather uneventful spring flood season, said Nick Carletta, a meteorologist with the National Weather Service in Grand Forks, N.D.

"For the most part we've dodged a bullet," Carletta said, adding that some parts of the valley, which stretches from Breckenridge, Minn., north to Fargo, Grand Forks and the Canada border, experienced minor to moderate flooding.

In nearly ever spot where water levels rose, however, the rivers are cresting or receding. With dry conditions forecast for this weekend and into next week, river levels are expected to continue falling.

Staff report

Southwest Minnesota

DNR: Stinky lakes are OK

The stench of sulfur emanating from some lakes in southwestern Minnesota isn't harmful and will soon disappear, according to the state Department of Natural Resources.

The odor, strong in some shallow lakes, represents a "perfect storm" of conditions including a long winter, depleting oxygen levels and killing off some plants, which anaerobic bacteria in the sulfur-rich soils then digest, according to a DNR statement. The process releases carbon dioxide and hydrogen sulfide, giving off the stink.

But the odor isn't harmful, officials say; in fact, water quality is typically good. The odor should dissipate when the ice goes out on the lakes, DNR officials said.

Pam Louwagie