When I'm wondering about weather folklore and historical events this is the man I go to. With more than 50 years of statistical and observational research, he's the dude! When it comes to lunar cycles, woolly bear caterpillars, insects, bugs, and animals, he tracks them, records them, and establishes ties to weather patterns. He's a knowledgeable and interesting man. His name is Steve Gottschalk by way of Lowden, Iowa. I'm grateful to him for lending his unique perspective to the site. Steve's "wild" world of weather can be found regularly right
here on TSwails.com. Take it away Steve!
IOWA'S DEADLIEST FLASH FLOOD
Without a doubt Iowa's deadliest flash flood occurred from late in the evening of July 4th to the early morning hours of the 5th, 1876. During the early evening hours of the 4th severe thunderstorms spawned several tornadoes killing at least 8 persons and injuring dozens of others across the state.
Later on slow, moving thunderstorms across N.E. Iowa produced torrential rains. An observer in Dubuque measured 4.30" of rain in less than 2 hours. At Rockdale, a tiny hamlet S.W. of Dubuque, located in the Catfish Creek Valley, much heavier rains fell. The deep waters within the valley prevented the citizens from fleeing the town.
After midnight, a dam on the mill upstream gave way unleashing a wall of water 20 to 30 foot high and many hundreds of feet wide into the town. All of the buildings in Rockdale were swept away and many of the townspeople were killed. The few survivors were found in the treetops. Reports said that 42 persons died in the flood.
IOWA'S EXTREME JULY RAINFALLS:
July 6, 1881 - Carroll County - 16.0" of rain in 3 hours caused extreme flooding.
July 3, 1939 - Manilla - 4.36" in 1.5 hours.
July 4, 1962 - Lake Okoboji - 10.0" in less than 4 hours.
July 4, 1981 - southern Iowa counties - 10" to 12" of rain caused $68 million damage & 3 deaths.
July 27, 1981 - Denison - 3.0" in 10 minutes.
July 2, 1999 - Parkersburg - 6.55" in 3 hours, Butler County - 11" to 14" fell.
IOWA'S EXTREME 24 HOUR RAIN TOTALS FOR JULY:
July 7, 1958 - Audubon - 12.53".
July 23, 2010 - Oelwein - 9.93".
July 17, 1996 - Mapleton - 9.77"
July 22, 2017 - Ionia - 9.30".
July 26, 1990 - Randolph - 8.93"
July 28, 2011 - Dubuque - 8.80".
July 1, 2018 - Ankeny -8.72".
SOME OF MY PERSONAL JULY RAINFALL RECORDS IN LOWDEN, IOWA:
July 26, 1985 - 0.20" in 1 minute. For a 10 second period I was measuring 0.01" per second.
July 1, 1983 - 1.0" in 10 minutes.
July 16, 2004 - 1.50" in 15 minutes.
July 4, 1973 - 2.91" in 40 minutes.
July 21, 1949 - 5.0" in 90 minutes. This was reported in the local newspaper.
On Thursday, our streak of 7 straight days with temps. in the 90's was broken by a big rain. We had 2.05" with 1.2" of that in 30 minutes. Our 7 days of 90's was only surpassed by 2012 and 1974 for the most 90s during the first 9 days of the month. 2012 had 9 and 1974 had 8. The 7 we had tied with 1989. It was our 2nd longest string of such days for the beginning of the month. We had our highest dew point yesterday with 77 degrees. The heat index hit 105 just as it had the day before. Next weeks blog will be on July's big hailstorms.
Say hey to Nimbus for me. On the "wild" side of weather...Steve
THE WEEKEND AHEAD
As expected Friday was a much better day around my area. Temperatures in the late afternoon were 2 to 6 degrees cooler than 24 hours earlier.
More important, dew points were down by 8 to 11 degrees. That knocked the heat index back more than 15 degrees. A very welcome change.
The break for dry weather does not last long as the threat of showers and storms returns Saturday afternoon and night. The dynamics are no where near as impressive as Thursday so rain totals should be light to moderate at best. Some areas may escape with no rain at all. Here's what the GFS and EURO show for rain totals through Saturday night.
After the weekend seasonal temperatures are expected until the end of next week. Scattered showers and thunderstorms are also possible in parts of the region as the central Midwest resides on the edge of some very intense heat just to the southwest. The ring of fire (as it's known) can be a very fertile and productive breeding ground for thunderstorm clusters with the ability to produce gusty winds and heavy rains. This needs to monitored closely the next 24-48 hours to determine more accurately the placement and potential amounts.
Then the focus turns to the potential for significant heat late next week and into the weekend. The EURO is still the most bullish with the northern extent of the heat. It has backed off a little since yesterday but remains quite aggressive generating heat index values of 100-110. Here is what the EURO shows for highs through July 20th. Heat index values the 17th-19th are in the range of 100-110 degrees. The Maximum high in Cedar Rapids is 97 the 18th.
You will notice the GFS is MUCH cooler never reaching 90 with several days in the 70s. I'm not sure why it has such a cold bias but I feel in the end it is probably too cool.
We may end up with a compromise which leans warmer towards the EURO solution. It will be interesting to watch the trends in coming days. No matter what happens, we still have a week before the threat of any serious heat. Have a great weekend and roll weather...TS