20 Year Anniversary of Historical March Tornado Outbreak

20 Year Anniversary of Historical March Tornado Outbreak:

Over the afternoon and early evening of Sunday, March 29, 1998 from 2:30 p m to 6:30 pm a widespread severe weather outbreak occurred across southwestern, south-central, southeastern, and central Minnesota counties.

Over 40 reports of large hail (up to 4.5 inch diameter in Nicollet County) came into the National Weather Service, and severe hail damage was reported to cars and trucks in Rochester.

Dozens of reports of strong winds (over 50 mph) were associated with thunderstorm supercells.

There were 14 confirmed tornadoes, the worst episode of March tornadoes in state history (and there have only been 10 tornado days during March in Minnesota history). Among these 14 tornadoes, an F4 (wind over 207 mph) was on the ground for 77 minutes and traveled 67 miles (Murray to Nicollet County). It was over a mile wide vortex at times. An F3 (winds 158-206 mph) tornado damaged many buildings in St Peter and on the Gustavus Adolphus College campus. Four F2 (113-157 mph) tornadoes caused damages in trailer parks, killed cattle in rural areas, and produced a good deal of structural damage in Le Center. Four F1 tornadoes (73-112 mph) caused damage to trees and rural buildings; and four F0 (winds 48-72 mph) tornadoes, mostly short-lived, were scattered across the landscape as well, the last one for the day in Wabasha County. Two days later on March 31 there was heavy snow and a blizzard warning issued for western Minnesota counties as a polar front invaded the Minnesota landscape.

These tornadoes caused just two deaths and 21 injuries—thanks to detailed forecasting by the NWS, acknowledged by many Minnesota citizens to be a superb job—but total estimated damages was in the hundreds of millions of dollars.

Further details from NOAA National Weather Service StormReports included the following:

F4 tornado hit parts of Murray, Cottonwood, Brown, Watonwan, Blue Earth, and Nicollet Counties. Most damage in Comfrey where 75% of structures were damaged, including the town hall; 100 people left homeless, 50 homes destroyed, school heavily damaged, and over 500 dairy cows killed.

F3 tornado hit St Peter destroying 500 homes and damaging 1700 others. Thousands of trees uprooted. Gustavus Adolphus Campus denuded of trees, and nearly 70% of all windows broken; hospital and churches damages, roof torn off library and 25% of the books were damaged, dozens of farms and rural homes were damaged as well.

Following these destructive storms there was a fourfold increase in the use of NOAA Weather Radio across the state of Minnesota as a means to provide all resides with timely information on severe weather watches and warnings.

A Footnote on Community Resilience in St Peter, MN: The storm struck on Sunday, March 29th precisely two weeks before Easter Sunday (April 12). The Catholic Church of St Peter was destroyed and not usable. So the congregation of First Lutheran Church in St Peter volunteered to share their building, and a joint Lutheran and Catholic Easter Service was held on April 12th. Thereafter for 2.5 years Catholic and Lutheran Services were alternately scheduled at the First Lutheran Church which also shared their building for Catholic weddings and funerals until November 2000 when a new church building for the Catholic Church of St Peter was consecrated and opened. There was a 20 year community remembrance held in St Peter on Thursday evening, March 29, 2018 hosted by former WCCO news anchor Don Shelby.

Preliminary March Climate Summary:

Average monthly temperatures around the state were either slightly below or slightly above normal by a degree or two. Extremes for the month were 59°F at Minnesota City (Winona County) on March 9th, and -16°F at Ely on the 10th. Minnesota reported the coldest temperature in the nation only four times.

Precipitation for the month was near normal, with greater abundance in western counties, and below normal values in some southern counties. Many southwestern Minnesota observers reported over 2.5 inches of precipitation and more expected to occur over this coming Friday and Saturday, the last two days of the month. Marshall, Winnebago, Vesta, and Canby reported over 20 inches of snow for the month, while some northeastern climate observers reported less than 4 inches.

Weekly Weather Potpourri:

Cherry blossoms are out in full force across Japan this week, making a beautiful blanket of pink across many landscapes. The BBC Weather Centre reported on this and displayed some beautiful pictures as well.

Meanwhile the National Park Service has pushed back the forecasted dates for peak cherry blossoms in the nation’s capital, Washington D. C. to the week of April 8-12, later than normal thanks to a cool temperature pattern.

A new study out of the University of Oklahoma examines the trends in surface water abundance among states across the USA. It finds that water poor states are seeing a decline in the surface area of waters, while water rich states are seeing an upward trend in surface water resources.

MPR listener question:

What were the temperature and dew point conditions in southern Minnesota leading up to the famous outbreak of tornadoes on March 29, 1998?

Answer:

Strong southerly winds brought warm air and lots of moisture up from the south. Temperatures across the southern part of the state that afternoon were in the high 60s F to low 70s F, with dew points in the low 50s F. These are high values for late March (record dew points are in the upper 50s F), but not typically associated with tornado outbreaks. The latent energy from the higher than normal dew points probably contributed to the severe weather, but it was also driven by a high degree of atmospheric instability.

Twin Cities Almanac for March 30th:

The average MSP high temperature for this date is 49 degrees F (plus or minus 13 degrees F standard deviation), while the average low is 30 degrees F (plus or minus 10 degrees F standard deviation).

MSP Local Records for March 30th:

MSP records for this date include: highest daily maximum temperature of 83 degrees F in 1968; lowest daily maximum temperature of 15 degree F in 1969; lowest daily minimum temperature of -3 degrees F in 1923; highest daily minimum temperature of 54 degrees F in 1967; record precipitation of 1.51 inches in 1933. Record snowfall on this date is 2.4 inches in 1934.

Average dew point for March 30th is 27°F; the maximum dew point on this date is 57°F in 1943; and the minimum dew point on this date is -11°F in 1969.

All-time state records for March 30th:

The all-time state high temperature for today's date is 87 degrees F at New Ulm (Brown County) in 1968; the all-time state low for today's date is -28 degrees F at Thorhult (Beltrami County) in 1975. The all-time state record precipitation for this date is 3.39 inches at Park Rapids (Hubbard County) in 1933. Record snowfall is 16.0 inches at Winona (Winona County) in 1934, one of the heaviest snows of the Dust Bowl Era.

Past Weather Features:

Early season thunderstorms brought heavy rains to many parts of Minnesota on March 30, 1933. Many areas reported over 1 inch of rain and some observers reported hail as well. Both Itasca State Park and Cass Lake reported over 2 inches of rain.


A winter storm rolled across southern Minnesota over March 29-30, 1934 bringing 6 to 16 inches to many areas of the state. Both Winona and Zumbrota reported over 17 inches of snow, a record for so late in the year.


The warmest March 30th in state history was in 1968 when sunny skies and south winds brought afternoon temperatures that were 20 to 30 degrees F above normal. Thirty-five climate stations reported a high temperature of 80 degrees F or greater. Even the nighttime temperature at Madison (Lac Qui Parle County) never fell below 51 degrees F.

By far the coldest March 30th in state history was in 1975. With ample snow cover still widespread across the state, a polar front dropped temperatures well below zero. Most climate stations in the state reported subzero morning temperatures and it was colder than -20 degrees F at Hallock, Argyle, Thorhult, and Waskish.

Outlook:

Snow/rain mix across the state on Saturday, with the heavier bands of snow in the north. Cooler than normal temperatures under partly cloudy skies through Sunday night. Temperatures will moderate on Monday, but there will be a chance for mixed precipitation around the state. Cool than normal temperatures will prevail next week with another chance for mixed precipitation (snow or rain) by Wednesday.