Land Care Report: Severe Weather and Storm Damage

A large fallen tree lies across a road

A fallen tree blocks Arboretum Drive near the Mills Street entrance.

On the afternoon of Wednesday, June 19, I was stuck in the Arboretum maintenance building after the crew left for the day, waiting for what appeared to be a benign rain shower to pass. I planned to walk back to the Visitor Center to finish my day in the office but didn’t want to get soaked in the rain. The rainfall had grown in intensity, but the blob on the radar wasn’t big and I figured it would pass soon. I had a land care article to write, so after knocking out a few emails on the computer at the maintenance building, I started writing it to kill time while the rain moved through.

My original idea was to write about the severe thunderstorms that moved through the evening of May 21. That storm caused widespread damage throughout the area, with winds exceeding 70 mph in some parts of Dane County. It caused the largest Madison Gas and Electric power outage in recent history. We had dozens of trees knocked down in the Arboretum. I got called in around 10 p.m. that night to clean up a cluster of trees that had fallen across Arboretum Drive. It took the land care crew days to finish clean-up on Arboretum Drive as well as the removal of fallen trees on services roads, trails, and in the gardens. There are still large trees down in some restoration areas that we’ll clean up this fall and winter before next spring’s prescribed fire season gets underway. Several of those trees were in isolated pockets, suggesting localized winds that were extra strong.

Broken tree trunks and downed limbs in a wooded area.
Damaged trees in the Grady Tract from storms on May 21, 2024 (Photo: Chris Kregel)

Well, that June 19 rain shower I thought would pass through in about ten minutes kept redeveloping right over the Arboretum. It lasted about an hour and dropped some of the heaviest rain I have ever seen. Before I could even finish the first two sentences of my article, I received phone calls about another fallen tree blocking Arboretum Drive. This time it was not due to strong winds but to saturated soil that could no longer hold the tree upright. It was shortly after 5 p.m. when I loaded up a truck with chainsaws and other gear, and the rain finally began to relent. My day would not be ending in the office as I had planned.

With the help of UW police and Arboretum ranger Stephanie Petersen, we cleared the tree and reopened the road by 6:30 p.m. But we didn’t even have the gear back on the truck when I received another phone call. This one was from a neighbor, calling to alert me that Marshland Creek was flooding Arboretum Drive. When I drove past that area on my way to clean up the tree, the adjacent land was flooded but the water hadn’t risen to the road. An hour or so later not only was the road flooded but the fast-moving water had also carried a lot of firewood logs onto the road, making it impassable. The National Weather Service flash flood warning wouldn’t expire until 8 p.m., and there was nothing to do but close the road for the night.

A road covered in water with logs scattered across it.
Marshland Creek flooded Arboretum Drive on June 19 and carried logs from a neighbor’s yard onto the road. (Photo: Stephanie Petersen)

With the police directing traffic, Stephanie and I drove a roundabout way to the maintenance building (we couldn’t take the flooded road) to get barricades for Arboretum Drive. By the time we placed the barricades and drove back to the shop, it was almost dark. Out of curiosity we checked the Arboretum rain gauge to see what that hour of intense rain had produced: we measured 4.55 inches!

The Arboretum did not sustain wind damage like it did in the May 21 storm, but that amount of rain in such a short time caused major erosion on some service roads. A few may be closed for weeks before repairs are completed. Other footpaths and boardwalks in low-lying areas were also flooded and had to be closed.

A wide trail washed out by heavy rains.
A washed-out service lane in Curtis Prairie after heavy rainfall on June 19, 2024.

As I finished writing this article on Sunday, June 23, yet another round of severe weather had moved through the area the night before. The Arboretum received another 1.10 inches of rain but avoided the worst of the storms and no major damage has been reported. But the active weather, and subsequent damage, over the last month makes one wonder what we’re in for as we go forward in time and these severe weather events become more common.

Earlier this year, Wisconsin had its first February tornado in recorded history amidst record high temperatures, and has already surpassed its annual average of 23 tornadoes per year. While reports are still being investigated, at least six tornadoes were confirmed from storms the evening of June 22. The ground is currently saturated from recent rains, and more trees could be susceptible to uprooting. Any additional heavy rain in the near future will exacerbate that issue, as well as service road erosion and footpath flooding. Responding to storm damage diverts land care staff time and energy that could be focused on restoration and other projects.

This heavy rainfall is all following on severe drought last year and very dry conditions the year before. Winter temperatures and precipitation have been just as unsettled, making our usual land management winter tasks harder to accomplish. And I recall having to remove a fallen tree from Arboretum Drive during the April election day snow storm this year. It’s frustrating to have our restoration work disrupted, but, unfortunately, more extreme weather and storm damage are likely a new reality at the Arboretum and throughout our region, and we’ll all have to be prepared to deal with it the best we can. (But at least it’ll get me outside and away from my desk!)

—Michael Hansen, land care manager