Summer Downpour

Saturday was one of those hot summer afternoons at the beach that ends with a downpour. One minute I was walking along a path at Gillson Park, enjoying a view of the lake between the sand dunes, smelling delicious slow-cook barbecue, and hearing the joyful hub-bub of kids splashing in the water…

The next moment the sky darkened, thunder rumbled in the distance. Lifeguards followed behind families who scrambled to collect their kids and gear, while dragging their roll-along coolers back to their cars. I beat a retreat myself, watching from my van as the parking lot emptied, and rain started cascading over the pavement:

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Since I had to wait for one of my kids, I was forced to slow down, and take a moment to consider the scene:

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Within minutes, the lower corners of the lot started to fill with water. It could have been a fun Nature Channel demo: What Happens When It Rains on Impermeable Surfaces. And I definitely could see why the proposed (but rejected) Lakefront Master Plan included parking lot rehab. But the situation quickly became somewhat worrisome, and I moved to a higher section of the lot as a shallow river starting forming along the south end:

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Finally, my son was ready to go, and we headed home, slowly pushing through puddles that swirled up along the edges of the eastside brick roads. I wondered how our block was faring, and had called home, so my husband could check things out and take a couple of pictures:

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In the past, our road has become impassable during sudden downpours like this one. I pulled into Wilshire Drive, then slowed down as we drove through water so deep, it splashed over the running boards:

downpour-drivethru-sm

Luckily, the storm cleared within about 90 minutes, and for the first time in recent memory, the storm sewers, though unable to keep up with the downpour, were continuously draining, instead of surcharging back into the street. Could the storm sewer relining program on Wilshire Drive and other streets be helping?

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As fast as it started, the whole thing was over. The next day, Sunday, was another gorgeous, crowded day at the beach. But in the trees near the overflowing parking lot, I could see storm runoff damage from the previous day’s storm:

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Now that we’re back to a sunny 80+ degree weather, it’s easy to forget all about rainstorms, runoff, and sewers. But to me, Saturday’s torrential downpour seemed like a little “nudge” from Mother Nature: Are you Rain Ready?


Links:

Visit the National Oceanic and Atmospheric Administration (NOAA) website to check observed precipitation or look up rain forecasts.

According to this NOAA observed precipitation map for Illinois on Saturday, July 18, the storm’s rainfall was probably under 2 inches. I’m still trying to find out how this compares to a so-called 2-year rain event.

For long-term trends, check out the NOAA Climate at a Glance stats for precipitation in northeast Illinois. As you can see in the next graph, we’ve been getting approximately .45″ more rain per decade since the 1890s, when the first Wilmette sewers were constructed. If this trend holds, our sewer systems will need to handle more–not less–severe weather in the future:

rain-trends-northeast-illinois

For more information on local Wilmette rain trends, check out this data reported by our water plant last summer:

…Over the past 34 years the Village has had four 100-year rain events, one
70-year storm, two 50-year rain events, four 25-year events, two 15-year storms and five 10-year storms.

Source: Village of Wilmette Municipal Services Committee, Meeting Minutes (August 25, 2014), p 3.


Updates: Added additional rainfall data (08-06-2015).

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