...Tornadoes...Snowstorms and Heat Waves,  Oh May!...          
   By: William R. Deedler, Weather Historian, WFO Pontiac/Detroit Mi

While March is generally considered one of the most volatile months in
Southeast Lower Michigan weatherwise, May doesn't pull any punches either! 
Scanning over a century's worth of weather records show some interesting 
and quite variable weather conditions during the month.

One of the strongest and earliest documented tornadoes in Southeast Lower 
Michigan occurred in May, 1896! While details are sketchy, evidently a 
massive tornado plowed across Oakland and Lapeer Counties on May 25th.
The tornado leveled numerous homes in the towns of Ortonville, Oakwood
and Thomas (no longer exists). In fact, parts of these homes were found 12
miles away! At least 47 people were killed, including nine people from one
house alone, along with approximately 100 injured as a result of this vicious 
storm. It's also interesting to note that May of 1896 turned out to be the second 
warmest May in recorded history at Detroit (perhaps the unseasonably warm
weather helped fuel the severe weather).

Some of the strongest tornadoes to hit Southeast Lower Michigan occurred in
the early to mid 1950's. The most noteworthy was the monster Flint/Beecher
tornado that occurred in 1953, but that storm hit in the month of June (8th).
(An in-depth article was written last June about this killer storm titled  "A
Southeast Michigan Twister Prototype"). Unfortunately, Genesee County was 
hit again just three years later on May 12th, 1956 with another devastating 
tornado (F4 on the fujita scale with a wind of 207-260 mph). After the Flint/
Beecher storm, this is the second strongest tornado to hit Genesse County.
Like its predecessor, this storm also formed in the Flint vicinity (3 miles east
of Flint) but then tracked southeast to 3 miles northwest of Atlas rather than
east. This tornado killed 3 people and injured 116 while taking out more than 
100 homes and five commercial buildings along its path. The average width of
the storm was about 300 feet and it is the last killer tornado to hit Genesse 
County (through April 1997). 

Just less than a month before the massive Flint/Beecher tornado on May 21,1953,
the first of two F4's (207-260 mph)  tornadoes ever to hit St. Clair county tore a 
mean path through the south side of Port Huron. By all accounts, the south side
of Port Huron was devastated by this twister. There were two deaths and 68
injuries along with an estimated 90 homes destroyed and another 300 damaged 
as the tornado ripped through the region. Also, along with the loss of homes, an 
additional 83 buildings were destroyed and another 124 buildings damaged. As
a severe thunderstorm moved northeast across St. Clair county, the tornado was
spawned just southwest of Port Huron over the town of Smith's Creek. The 
tornado then took aim on the south side of Port Huron, reaching nearly a mile 
wide across at its worst as it tore through the area on its way into Canada.



The second F4 tornado to hit St. Clair county also occurred in May...May 8th,
1964 The tornado actually developed over Macomb County, 3 miles north of
Mt. Clemens, then plowed east northeast across New Baltimore to just north of
Algonac, in extreme southern  St. Clair County,  before crossing the St. Clair 
River into Canada. This tornado killed 11 people and injured more than 200 as
it destroyed 132 homes and damaged another 240 homes and farms. But this 
tornado wasn't the most damaging in St. Clair County. That distinction belongs
to an F3(158-206 mph) tornado that hit St. Clair and Macomb Counties also in
May...May 2nd, 1983. The tornado was again spawned over Macomb County,
this time over the extreme southeast portion of the county near Eastpointe. The
storm then blew across Lake St. Clair and into Harsens Island and damaged or
demolished 25 to 30 homes, an aircraft hangar and a large building. The estimated 
cost of the damage was over $5 million.

While a few snow flurries or snow showers are all not that rare in Southeast
Lower Michigan in the month of May, the following two snowstorms were...

One storm occurred May 21st-22nd, 1883, while the other, the more documented
of the two, hit the area May 9th, 1923. The snowstorm on May 9th, 1923 was 
probably the most severe and extensive over Southeast Lower Michigan of the
two (another, more in-depth article was written about this storm last May titled
"Snowstorm of May 9th, 1923") Records at Detroit show a six-inch snowfall by 
the evening of the 9th, while further north and west of the city it was even worse! 
Six to nine inches fell across the Ann Arbor area north into Howell and east, across 
Pontiac and Port Huron. Even more incredible, snow depths flirting with a foot 
were observed from Lansing and Flint area, north into the Saginaw Valley and 
Thumb Region. Widespread damage occurred when such a heavy wet snow fell
on top of the newly sprouted spring vegetation. Afternoon and evening temperatures
hovered in the lower to mid 30s, while a bitter cold (particularly for May) northwest
wind blew at 15 to 25 mph.
. 
The May 21st-22nd, 1883 snowstorm by the date alone sounds almost unbelievable!
Very little was written in the archaic Detroit weather records about the storm at 
the time. In fact, the snowstorm was not confirmed until much later (1904), since 
officially continuous snowfall records did not start until 1885. The following is
from the official observation form...

                                                         May 21, 1883
            Rain began at 900am. Snow from 250pm to 910pm. Hail 934am to
           1005am and 110pm. Strong wind reaching 36 mph from the North.
           Temp from 32.5  to 46.0. Baro rising.

                                     

                                                         May 22, 1883
           Hail ended during the night. Snow began during the night. Rain and 
           snow  ended 1005am. Northerly wind reaching 28 miles. Temp from  
           32.5 to 41.0  Snowfall estimated by Inspector Conger to have been 
           5.0 in - on 21st&22nd    (This entry made April 28, 1904 - CDC.J)

The snowfall was split between the two days and recorded as 2.3 inches on the
21st and 2.7 inches on the 22nd. While hail was a likelihood, especially in the
afternoon on the 21st as the colder air moved in, I suspect the hail recorded 
overnight into the 22nd could have well been sleet. One may also wonder with
such cold air advected into the region at the surface and aloft in late May,  if 
thundersnow (sleet/hail) didn't also occur somewhere over Southeast Lower 
Michigan, especially with accumulating snow. This snowfall is by far the latest
measurable snowfall recorded in Metro Detroit. The next closest, heaviest 
measurable snowfall date-wise is 1.5 inches, which fell on May 13th, 1912 and 
then, our other big storm with the total of six inches on May 9th, 1923. The latest
snow was officially observed in Detroit was the last day of May...May 31st, 1910
when a trace fell. By the way, it's interesting to note that not one of the pre-
mentioned Mays with measurable snowfall placed in the top 10 coldest Mays in 
Detroit.
 
Now, from one extreme to another, lets look at Heat Waves. While there have been
hot days in May with records into the 90s, there are only two years that had extended 
periods of hot weather in May and those are 1962 and 1977. The hottest and more
consecutive of the two was in 1962 when from May 14th-May 18th, the daily high
temperature climbed to ninety or above. This hot spell created five new consecutive
record high temperatures which still stand to this day. In 1977, there were also five
new record highs established but they were not consecutive, nor all in the 90s
(see: Table, below).

                            1962                                                                     1977
DATE.............RECORD HIGH..........................DATE..............RECORD HIGH
5/14                         91                                        5/13                          89    
5/15                         92                                        5/20                          91
5/16                         92                                        5/21                          92 
5/17                         93                                        5/24                          87 
5/18                         93                                        5/25                          89
         
Both Mays placed in the top ten hottest Mays in Detroit with 1962 placing 3rd and
1977 placing 5th. Relatively recently, May of 1991 placed at the top of the list for
the warmest May but ironically, not one record high temperature was set that month.



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