Wisconsin Weather

Wisconsin Weather - The Worst Storms of 2018

The Wisconsin Weather team covered 54 storm events across Wisconsin in 2018. Historic blizzards, flooding heavy rain, and tornado outbreaks...2018 had it all. Before we close the door on the past and move toward the future, let's look back one last time.

Here are the three events that stick out the most this year...

The Top Three Worst Storms of 2018

#3. August 28 Tornado Outbreak from Marquette to Sheboygan County

Wisconsin Weather
Storm reports from the August 28, 2018 tornado outbreak

When a Wisconsin tornado outbreak takes third spot in worst storms list, you know it's been a crazy year!

A strong complex of thunderstorms and embedded supercell tracked across Marquette and Green Lake counties during the afternoon on Aug 28, 2018. 19 tornadoes were reported stretching from Marquette county, east through Sheboygan county. There was 1 EF2 tornado, 13 EF1 and 5 EF0 tornadoes. The amount of damage to trees and agricultural was staggering. Heavy rainfall was once again a big deal with 7.3" of heavy rainfall over a 72HR period in Fond du Lac, WI!

I chased this storm from Montello to Ladoga. I remember driving east on HWY 23 into a very turbulent headwind...a current of energy flowing into the large thunderstorm. This storm featured a large mesocyclone close to the ground with smaller tornadic circulations rotating around like a carousel. Hunter Anderson provided live coverage on the Wisconsin Weather facebook page making this one of the most well covered tornado outbreaks in state history!

Wisconsin Weather
A tornado producing wall cloud (no visible tornado at the time) south of Ripon Wisconsin. The tornadoes were often wrapped in rain.

Today you can still see the storm damage on Interstate 41 between Allenton and Lomira.

Since the start of Facebook, reporting and identification of tornadoes has become much easier. Many of these tornadoes found are weak EF0-EF1 with wind speeds less than 100MPH. In the past most of them would be considered straightline wind damage. Historical comparisons should be made on the strength of tornadoes, not the quantity. Frequency of major tornadoes EF3+ remain very low. In other words, expect more record breaking outbreaks in the future simply as a result of sensitivity. Lets hope the tornadoes stay on the weaker side of things.


#2. Record Breaking 15" of rain in Cross Plains, WI.

Wisconsin Weather
15.33" of rain in Cross Plains, WI on the night of Aug 20, 2018. This image simply shows the area most impacted.

15.33" of rain in Cross Plains, WI on the night of Aug 20, 2018. This broke the previous Wisconsin 24 HR rainfall record of 11.72" in 1946. Record setting rainfall occurred across the western portions of Dane county. There were a number of reports of 10-13 inches from just north of Verona to Middleton to Cross Plains along US Highway 14. Reports from Cross Plains to Black Earth are that these areas were completely submerged. Large rescue effort were needed to evacuate people to higher ground.

Wisconsin Weather
Screen capture of our interactive radar map on the night of Aug 20, 2018

15" of rain is almost half the annual precipitation in about 12 hours! Get used to it. We think these events will become more common as the sun approaches grand solar minimum in the next two decades. If you want to learn more about grand solar minimum and what it means for Wisconsin winters, click here. This event was one of several heavy rain events in the summer of 2018. The previous week Watertown, WI received 8.6" of rain in one day! Both events were associated with abnormal upper level 500mb cold anomalies (see below)

Wisconsin Weather
Negative 500mb height anomaly over southern Wisconsin on August 20, 2018 associated with heavy rainfall events during the month.

We called this storm event a CLASS 4 - SIGNIFICANT storm. We didn't give it a 5 because it was relatively localized. There is no question it re-wrote the record book for daily max precipitation.


#1. The Historic Blizzard of April 2018

Wisconsin Weather
Snowfall map from the April 13-15, 2018 Blizzard.

This record-breaking snow storm brought nearly three feet of snow to central Wisconsin! On the weekend of April 13-15, 2018 it was possible for a single location to experience large hail, heavy rain, thunderstorms, freezing rain, sleet, heavy snow, blizzard conditions and blowing snow! Weather from every season in one event!

It started on Friday with a supercell thunderstorm producing large hail as it tracked from Praire du Chien to Sheboygan. Over 12" of snow fell Friday night into Saturday near Amherst Wisconsin but that night was mainly remember for the freezing rain.

Picture of large hail by Joe Walker in Fairwater, WI on Friday, April 13 2018
Picture of large hail by Joe Walker in Fairwater, WI on Friday, April 13 2018

By Sunday colder air flooded in turning everything to snow. A large area of 15 to 30 inches of snow fell across central Wisconsin. Winds gusting over 45 mph rewrote the record books for many locations across the area. 33" of snow in Amherst, WI, 30" in Tigerton.

The heavy weight of the snow caused several roofs to collapse. Part of a roof at a motel in Green Bay collapsed over the pool area, and roofs of several barns in Brown and Outagamie counties were damaged. The storm brought blizzard or near-blizzard conditions to much of the area and made roads impassable from time-to-time. Winds of 35 to 50 mph caused sporadic power outages and created waves of 10 to 16 feet on Lake Michigan. The persistent northeast wind created shoreline erosion along the western shores of the lake. Many businesses were closed for part or all the weekend. There were almost 1,900 snow reports from the event. In addition to the snow, freezing rain up to 0.6" accumulated in central and southern Wisconsin.

Wisconsin Weather
From the Shawano County Sherrifs Office after 30" of snow plus drifting

This was a "once in a lifetime" event. This storm broke snowfall records back to 1880 in Green Bay! We gave it a CLASS 5 - HISTORIC rating because when we look back at 2018 we will always think of this storm first! I wonder what the chances are we see another one of these in the next three years???


That's it for our list!

Other notable events include the June 16, 2018 Heavy Rain in northwest Wisconsin and heavy rain in southern Wisconsin on August 17th. The April 3rd snowstorm and 25" of lake effect snow on January 15 in Door county. There were stretches of excessive heat for the holidays including Memorial Day Weekend and late June, and record cold for New Years and April.

Your list of top events may be different depending on where you live. What your top three storm events of 2018? Let us know by commenting below or on Facebook!

Click here to browse through the list of 2018 storm events

2018 Wisconsin Storm Event Facts

  • 54 - Total events.

  • 10 - Minor/None. Having little to no impact on Wisconsin. Barely worth mentioning.

  • 26 - Low - Certainly having an impact. A nuisance more than anything.

  • 16 - Moderate - Somewhere between nuisance and significant.

  • 3 - Major/Significant - The biggest storms.

  • 1 - Historic/Legendary. The Blizzard on April 13-15, 2018 was the most impactful event of the year. Special storms that are a notch above the rest.

February, May, and August were the most active months with 6, 6, and 5 storm events respectfully. December so far has been the most quiet month of the year. We still have 17 days left to change that.

Wisconsin Weather
Storm events with a class of 2+ by month

About Storm Events

"Storm Events" is a unique service created by Wisconsin Weather in 2017, further perfected in 2018. A storm event is created at the first sign of a storm 7+ days before it occurs and evolves overtime. The system is used for multiple things such as organizing our forecast materal in the days ahead to grouping all website activity into buckets after the event ends.

Storm Class is a severity scale from 1-5 (worst). It is based on forecaster perceived total social, economic, and historical impact on Wisconsin as a whole. A storm can be terrible for some and have no impact on others. There was little/no consideration for number of storm reports, spatial distribution, or life/property damage. It's mostly a feeling.

Storm report numbers can be largely inflated or deflated for many reasons therefore not a measure of severity. I included it mostly for entertainment.

We started keeping track of storm events in 2017. 2018 is the first full year. Someday we will backfill storm events so we can make historical comparisons. It is still a work in progress and only gets better with time.

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