New Report: Extreme downpours on the rise in Michigan

Despite drought, extreme precipitation events occurring

Environment Michigan

Michigan — Less than three months after a major rainstorm in Flint led to nearly four feet of water on the roadways and flooding of area businesses and homes, a new Environment Michigan Research and Policy Center report confirms that extreme rainstorms are happening 37 percent more frequently in Michigan since 1948.

“As the old saying goes, when it rains, it pours — especially in recent years as bigger storms have hit Michigan more often,” said Nic Clark, Michigan campaigns director for Clean Water Action, which joined the center in announcing the release of the report. “We need to heed scientists’ warnings that this dangerous trend is linked to climate change, and do everything we can to cut carbon pollution today.”

Based on an analysis of state data from the National Climatic Data Center, the new report found that heavy downpours that used to happen once every 12 months on average in Michigan now happen every 8.8 months on average. Moreover, the biggest storms are getting bigger.

The largest annual storms in Michigan now produce 12 percent more precipitation, on average, than they did 65 years ago. The largest annual storms nationwide now produce 10 percent more precipitation, on average, than they did 65 years ago.

“Scientists have concluded that the rise in the frequency and severity of heavy rainstorms and snowstorms is linked to global warming. Warming increases evaporation and enables the atmosphere to hold more water, providing more fuel for extreme rainstorms,” said Nathan Willcox, federal global warming program director for Environment America. “At the same time, however, that evaporation increases soil dryness. Moreover, scientists expect that periods with relatively little precipitation will tend to mark the periods between heavy rainstorms. As a result, droughts are likely to become more frequent and severe in some regions of the United States.”

Currently, more than half of the lower United States is suffering through prolonged drought, aggravated by the fact that the last six months have been the hottest January-June period on record.

Nic Clark with Clean Water Action pointed to the rainstorm that hit Michigan in June of 2011 as an illustration of what more extreme rainstorms could mean for the state. That storm dumped six inches of rain, on average, over a 12 hour period. The storm waters swamped homes and roadways and some rescuers in Lansing were even deployed to evacuate people.

The new Environment Michigan Research and Policy Center report, When It Rains, It Pours: Global Warming and the Increase in Extreme Precipitation from 1948 to 2011, examines trends in the frequency of and the total amount of precipitation produced by extreme rain and snow storms across the contiguous United States from 1948 to 2011.

Using data from 3,700 weather stations and a methodology originally developed by scientists at the National Climatic Data Center and the Illinois State Water Survey, the report identifies storms with the greatest 24-hour precipitation totals at each weather station, and analyzes when those storms occurred. The report also examines trends in the amount of precipitation produced by the largest annual storm at each weather station.

Environment Michigan Research and Policy Center and Clean Water Action highlighted two proposals from the Obama administration — fuel efficiency standards for cars and light trucks and the first ever carbon pollution standards for new power plants — as critical steps toward meeting these pollution reduction targets.