2021 Montello-Princeton-Zion, Wisconsin tornado

the 2021 Montello-Princeton-Zion, Wisconsin tornado was a extraordinarily violent, large and long-tracked EF5 tornado that hit the towns of Montello, Princeton, Rush Lake and Zion in Wisconsin on March 28, 2021.

The strongest tornado of the Tornado outbreak sequence of March 26-April 2, 2021, and was the strongest on record in Wisconsin. It was the third known F5/EF5 to strike Wisconsin since 1950.

Despite the supercell being very discrete, and the tornado being extremely violent, only a weak hook echo with a debris ball was visible for the lifetime of the tornado on radar. The tornado also caused damage comparable to that of the 1997 Jarrell, Texas tornado, however was also very slow moving, just like Jarrell.

Meteorological setup
On March 28, 2021, a intense storm system was tracking across the United States. The Storm Prediction Center had placed the region under a moderate risk for tornadoes in the 1:00 am CDT outlook, due to sufficient instability for a potentially large tornado outbreak. At 8:00 am CDT, the National Weather Service in Milwaukee launched a weather balloon, which found a extremely unstable atmosphere existed, and returned PDS TOR as the possible hazard type, and with further destabilization, by the 11:30 am SPC outlook, the SPC had marked a high risk of tornadoes for much of Wisconsin. By 1:00 pm CDT, the Storm Prediction Center had issued a PDS tornado watch for the region, with a >95% chance of two or more tornadoes, and a 90% chance of one or more strong to violent tornadoes. And by 2:00 pm, nearly 20 discrete supercells were in progress across the region.

The tornado -
At 2:04 pm CDT, the National Weather Service in Milwaukee issued a severe thunderstorm warning on a long-tracked supercell, the warning noted the fact that the storm was a supercell, and could produce a tornado at any time. At 2:15 pm, the supercell produced it's first tornado, roughly 10 miles northwest of Montello, which caused EF2 damage to several outbuildings, and warranted a tornado warning at 2:16 pm for the Montello area. Spotters reported a funnel cloud at 2:23 pm over forested areas, and the tornado touched down over a field at 2:25 pm. The tornado near directly struck a well-built house very early on in it's lifetime, at 2:26 pm, causing EF1 damage to the structure. However, damage to corn crops in the field behind the house shown EF2 intensity was likely occurring at this point. The tornado hit two houses, causing EF2 damage to both of them at 2:27 pm, and at 2:28 pm the tornado crossed into Lake Montello, briefly moving back onshore, causing EF2 damage to several houses. And by 2:30 pm, the tornado moved back onshore, causing mostly EF1-EF2 damage, with one house having it's outer walls knocked down, suggesting EF3 intensity. The tornado then continued into rural areas by 2:34 pm, where it would spend most of it's life, it likely underwent explosive intensification around 2:40 pm, as a homestead was partially swept from it's foundation at 2:41 pm, suggesting EF4 intensity. The first signs of EF5 intensity began occurring at 2:45 pm, with ground scouring around 2 to 3 feet deep, and trees being uprooted. The first solid evidence of EF5 intensity however, occurred at 2:46 pm, when a anchor-bolted house was directly hit, being swept clean from it's foundation, left with just a bare slab, 3 deaths occurred at this residence. The tornado proceeded over cornfields, and caused ground scouring of 3 feet deep between 2:46 pm and 2:48 pm. Another house was largely swept clean at 2:49 pm, with EF5 damage occurring here as well. Miraculously however, no one was injured at this residence despite the lack of a basement.

The tornado slightly weakened at 2:51 pm, causing high-end EF4 damage to a house at 2:52 pm, before crossing a very small lake at 2:53 pm, re-intensifying into a EF5 tornado in the process, 2 houses were left with bare slabs by the tornado at 2:56 pm, and the National Weather Service in Milwaukee issued a tornado emergency for the area at 2:57 pm. The tornado started to accelerate slightly at 3:00 pm, striking White Lake Beach Resort at 3:02 pm, causing widespread EF4 to EF5 damage. Some of the most extreme damage of the tornado occurred here, with one house having it's anchor bolts snapped, and being left with a bare slab. No survivors were documented in the northern neighborhoods of the resort, resulting in 30 deaths. The tornado crossed 19th Avenue at 3:05 pm, striking a vacant lot and a church at 3:06 pm, causing EF5 damage to the church and nearby structures, one of which was a well-built two story home left with a bare slab, no deaths occurred at that location. The tornado missed a farm at 3:08 pm, causing EF2 structure to much of the farm's structures and equipment.

Ground scouring neared 4 feet deep in spots between 3:10 pm and 3:20 pm, as the tornado hit no more structures until 3:16 pm, when two houses sustained a near-direct hit, resulting in EF5 damage to both of them. The tornado weakened slightly at 3:18 pm, to a low-end EF5, causing EF5 damage to a trailer and car at 3:20 pm. A lodge just across the street suffered a direct hit, with another 5 people dying, and almost every structure at the lodge being left with a bare slab, suggesting winds of around 220 mph. The tornado struck a farmhouse at 3:24 pm, causing EF5 damage, with only a bare slab being left behind. Ground scouring once again picked up to around 4.5 to 5 feet deep. The tornado missed a auto shop at 3:27 pm, causing EF3 damage to the structure of the auto shop. The tornado entered Princeton city limits shortly after, causing widespread EF5 damage, leaving nearly a dozen houses with bare slabs. The tornado proceeded into Princeton at 3:30 pm, causing extreme damage, with a Piggly Wiggly supermarket being directly struck, leaving only a bare slab on the very well-built structure, suggesting winds of 250 mph. Nearly 100 houses in Princeton sustained EF5 damage from this tornado, and the tornado exited the city limits at 3:34 pm as it started to speed up significantly. The tornado peaked northeast of Princeton at 3:40 pm, with estimated peak winds of 266 mph (428 km/h) occurring at a farm. Ground scouring near here also reached nearly 6 feet deep, a house just west of the barn also was swept from it's foundation, leaving a slab. The tornado from here entered very rural areas, not striking another structure until 3:44 pm, when a well-built home was partially swept from it's foundation, suggesting EF4 intensity. A two-story home was directly hit at 3:45 pm, with only a bare slab remaining. Damage here suggested winds of nearly 240 mph, and 10 died in this movement over rural areas. Another house sustained a direct hit at 3:45 pm, also being left with only a bare slab.

After this, the tornado shrunk and once-again entered rural areas, not hitting another house until 3:48 pm, when 2 houses near each other both sustained EF5 damage. Many thought the tornado was weakening, with a weakening tornado vortex signature on radar and visibly shrinking, however it was still very capable of producing EF5 damage by this point, and after crossing the Fox River at 3:53 pm, it once again hit two houses, causing EF5 damage to both of them. The tornado, still a EF5, continued over fields, causing ground scouring of 2 to 4 feet deep between 3:54 pm and 4:00 pm. A well-built two-story home was nearly directly struck at 4:01 pm, with EF5 damage occurring here, with the structure left with a bare slab. A ranch was struck by the tornado at 4:05 pm, now a high-end EF4, with the ranch swept from it's foundation. However, the presence of debris on the foundation warranted a rating of 190 mph here, a barn sustained EF3 damage at 4:08 pm, however was not directly struck. The tornado once again re-intensified into a EF5 tornado over fields at 4:10 pm, with ground scouring near 4 feet deep occurring, a house was struck at 4:11 pm, with EF5 damage occurring here.

A strengthening tornado vortex signature shown that the tornado had recycled itself, and another house sustained damage indicative of winds of 240 mph at 4:13 pm, or mid-range EF5. For the next 5 minutes, the tornado was over a large cornfield and very little is known about the tornado at this point in it's life, however the tornado did strike a group of buildings at 4:18 pm, causing EF5 damage to all of them. Finally, the tornado entered Rush Lake at 4:23 pm, causing widespread EF4-EF5 damage, another 14 people died in Rush Lake. One house in Rush Lake was left with a bare slab, and the foundation was partially lifted. The anchor bolts here were also snapped, indicative of winds of 250 mph. The tornado finally weakened below EF5 intensity for the final time at 4:29 pm, over wooded areas, and soon enough crossed over Rush Lake as a high-end EF4.

The tornado caused low-end EF4 damage to a house at 4:33 pm, before taking a sharp turn northeast, another house sustained a hit by the tornado at 4:38 pm, with high-end EF3 damage occurring, this is where the final 10 deaths of the tornado occurred. By 4:45 pm, the tornado was a mid-range EF3 cone tornado, and was visibly much weaker from it's peak just over a hour earlier, various houses sustained EF3 damage as the tornado proceeded over rural areas. The tornado just narrowly missed the town of Zion at 5:09 pm, as a high-end EF1, and the tornado lifted just west of Oshkosh at 5:15 pm, after 2 hours and 50 minutes on the ground, and a 40.15 mile long track.

Aftermath
The Governor of Wisconsin declared a state of emergency late on March 28 following this tornado and several other destructive tornadoes, including a EF4 tornado in Milwaukee. In the end, the National Weather Service storm survey determined that 72 people were killed in this tornado, and rated it a EF5, the highest rating possible on the Enhanced Fujita Scale. The areas effected by the tornado were declared a federal disaster zone by President Donald Trump on March 29. The tornado was determined to be the strongest in Wisconsin state history, with winds of 265-270 mph occurring at peak intensity. Ground scouring suggests the tornado could've been even stronger briefly, with winds possibly nearing 295-300 mph at one point.