Tom and Diane Peterman tried to buy flood insurance when they moved to their retirement home on the shores of Black Lake 14 years ago but were told it was
n’t available. John Solum was told he wasn’t in a flood zone when his family bought a 1940s-era cabin there.
Then came this spring’s historic a
nd devastating floods across northern Michigan — in some areas, for the first time anyone can remember — swamping homes, pushing dams to the brink of failure and washing out roadways. Dozens of counties were under a state of emergency.
Black Lake was so high that floating ice broke apart decks and crashed through windows.
“We’ve never seen anything like that. Never,” said Solum, who experienced flooding
often when he lived in Houston. Knee-high floodwater forced them to tear out flooring, drywall, furniture, bedding and appliances.
Across Michigan, thousands were left without financial protection after record April rains fell on top of record March snowfall. Worse, many had no idea they were at risk despite years of increasingly heavy precipitation.
Their experience exposes vulnerabilities across the country, experts say, because flood plain maps d
on’t cover all areas. What’s more, the federal government’s mapping method is arguably outdated and does not account for actual risks as climate change increases the odds of more extreme weather.
The Federal Emergency Management Agency develops and updates maps that determine who’s in a flood plain and must buy insurance, and to help communities plan.
But it hasn’t developed maps in many less-populated areas, including some Michigan counties that experienced unprecedented flooding.
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Black Lake, for example, straddles two counties — Cheboygan, which has a 2012 FEMA flood plain map, and Presque Isle, where most areas have never been mapped.
The longtime summer and retiree destination is ringed by small cabins and some larger homes.
Another issue: FEMA’s maps are based on risks of rivers, streams and other waterways overflowing their banks. But they don’t account for flooding caused strictly fro
m increasingly heavy rainfall that overwhelms stormwater infrastructure in urban areas and inundates rural towns where there’s nowhere for the water to go.
First Street, a company that researches the financial implications of climate change, found more than twice the number of properties at significant flood risk nationw
ide after incorporating that rainfall data into its own models and by mapping the whole country, including smaller streams that FEMA does not.
That includes four times more properties in Michigan.
“I couldn’t believe it when we first started building our model how different we were from FEMA,” said Jeremy Porter, chief economist at First Street, who says federal maps are “missing a whole source of flooding.”
FEMA uses that extra rainfall data to help set insurance rates, experts said. But it’s unclear whether it’s proceeding with an effort to incorporate it into flood plain mapping.
The General Accounting Office, a federal watchdog agency, raised concerns five years ago that FEMA’s flood hazard maps didn’t reflect the best available climate science or heavy rainfall.
FEMA declined an interview request, but said in a statement that 95% of the U.S. population lives in areas with maps, which are “snapshots in time.” It did not respond to q
uestions about whether this year’s flooding adds urgency to mapping less-populated areas or whether it’s updating its mapping methods.
