Sunday, July 30, 2023

Rethinking 100 year storms


The Winooski River in Vermont seldom makes national headlines, and when it does it’s usually ungood. The Great Vermont Flood of 1927 wiped out more than 1,200 bridges and killed 84 people, including Lt. Gov. Hollister Jackson, who drowned trying to cross high water in his automobile.

An ice jam in 1992 and Tropical Storm Irene in 2011 were other significant events for the Winooski (the name is a derivation of an Indigenous word for “onion,” reflective of the wild ramps or leeks that grew on its banks) a 90-mile tributary emptying into Lake Champlain near Burlington.

Recently, a single storm dumped two month’s worth of rain on parts of New England, turning Montpelier into a lake, but fortunately leaving all of the state’s politicians upright. In the Adirondacks, communities including Newcomb, Long Lake and Saranac were hit particularly hard, with road closures, flooded highways and crumpled pavement.

The 5.28-inches of rain that fell in Montpelier is characterized as a “100 year storm,” meaning that in any given year there is a 1% chance of it happening. Yet the city received almost exactly the same amount just a dozen years ago.

If it seems to you that these 100-year storms are coming around more frequently than they should, you would be right. So the numbers are pretty clearly in need of revision. This year the National Oceanic and Atmospheric Administration received a congressional appropriation to update its 1-in-100 year map, with results expected in 2027.

Meanwhile, the First Street Foundation has released its 8th National Risk Assessment, showing how climate change is making these rare events more likely. It shows that for just over half the population, a 1-in-100 year event in their communities is now a 1-in-50-year event, while in some areas, affecting 1.6 million people, storms that previously had a 1% chance of occurring in any given year now stand at 10%.

“(T)he levels of rainfall associated with extreme precipitation events that have been experienced historically are rapidly becoming more frequent and may be the ‘new normal’ in many parts of the US — all due to the changing climate,” the report states.

A county-level map of the nation (pictured above) shows severe-event frequency relatively unchanged in the far-northern Adirondacks, but increasing further to the south. In Essex County, what previously was a 100-year storm is now roughly a 50-year storm, while further to the south and west to Herkimer County, a 100-year event is now a 20-year event.

 In response to the destructive flooding experienced by the central Adirondack communities of Long Lake, Indian Lake, and Blue Mountain Lake, Adirondack Foundation is activating its Special and Urgent Needs (SUN) Fund to coordinate and distribute support to the communities where it is most needed in the days, weeks, and months to come.

 The SUN Fund was initially established to help Adirondack residents after Tropical Storm Irene, and later used to financially support vulnerable populations impacted by COVID-related business closures and other cascading fallouts.

Community members interested in donating to this fund can find more information online or can contact Leslee Mounger at or (518) 523-9904.

This first appeared in Adirondack Explorer’s weekly “Water Line” newsletter. Click here to sign up.

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Tim Rowland is a humor columnist for Herald-Mail Media in Hagerstown, Md., and a New York Times bestselling author. His books include High Peaks; A History of Hiking the Adirondacks from Noah to Neoprene and Strange and Unusual Stories of New York City. He has climbed the 46 high peaks, is an avid bicyclist, and trout tremble with fear when they see his approaching shadow. He and his wife Beth are residents of Jay, N.Y.

3 Responses

  1. Billy says:

    Ungood? 😉

    But, there is a slight difference between the storms. The one 12 years ago was the remnants of a hurricane, and those are not overly common as far inland in the Northeast as this one was.

    The more recent storm is just a large version of an everyday rain storm.

  2. Robert DiMarco says:

    Just like along the Mississippi might have to consider moving awaynfrom the rivers. Be hard to do in vermont but mother nature has the last word

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