Nothing quite solidifies the summer experience more than a hot 4th of July by the pool, accompanied with a tasty barbecue and closing out with a fantastic fireworks display in the evening. Unfortunately, this optimal version of July 4th celebrations doesn't always pan out the way people hope, with the weather playing an important role in shaping each holiday. As the United States celebrates its 249th year of Independence, let's take a look back at some of the more notable weather events in history that transpired on the nation's birthday.
What better place to start than the first Independence Day. Despite being nearly a quarter of a millennium ago, we have enough records that have survived to help give us a picture of how the nation's first official day of independence from the British looked.
None other than the well known weather obvserver, Thomas Jefferson, do we have to thank for these records on July 4, 1776. Beyond being the author of the Declaration of Independence, Jefferson was also an adamant weather enthusiast and known to keep track of weather observations. Starting July 1st, 1776, Jefferson would go on to record each day's weather until just before his death in 1826.
A look at Jefferson's weather observations from July 1776.
Jefferson, who was in Philadelphia when the Declaration of Independence was adopted, made several observations throughout the day on July 4th. The morning started our with temperatures of 68°F, rising to 76°F by 1 PM. Another weather observer in the area, Phineas Pemberton, also mentioned there was an increase in afternoon clouds as well as a drop in barometric pressure.
A line of thunderstorms pushed southeastward out of Michigan during the evening of July 4th, 1969 and progressed onward into eastern Ohio. By the time the line of storms crossed into Ohio, it strengthened into a major derecho, slamming Toledo, OH with winds locally gusting over 100 mph and several downed trees across the city. Similar wind speeds were reported in the Cleveland area after 8 PM. The line of storms continued east into western Pennsylvania during the late evening hours, eventually weakening by the time it neared its southern border.
Radar showing the bowed derecho from Akron, Ohio.
The timing of this derecho could not have been worse, occuring during the peak time frame for evening fireworks displays across the region. Eighteen people unfortunetly lost their lives in Ohio alone, at least three of which were watching fireworks from small boats on Lake Erie. Over one hundred boats were toppled or destroyed on Lake Erie.
Hand drawn map of the Derecho's Storm Track (Courtesy of NOAA)
A long lasting derecho originating in Minnesota developed during the morning of July 4th, 1977, starting what would be a long trek across the Upper Midwest. After a weak start, the line of storms strengthened early in the afternoon as it neared Minneapolis, MN. The derecho raced through northern Wisconsin through the afternoon and early evening, crossing into Michigan by sunset before falling apart near Detroit, MI.
The derecho lasted a total of 15 hours and brought a band of damaging wind gusts, particularly the most severe across Wisconsin. Nearly 850,000 acres of woodlands in Wisconsin were badly damaged. Winds of 135 mph were also estimated in Flambeau River State Forest. One woman was unfortunately killed when a tree fell on her camper.
Radar and Satellite View of the Derecho over Canada
Another derecho event occurred on July 4, 1999, proving to be even more long-lasting than the one mentioned above. Over the span of 22 hours and crossing 1,300 miles from North Dakota to Maine, this storm was particularly damaging as it led to over $100 million in damages and resulted in four fatalities.
The initial area of storms started in North Dakota near Fargo during the predawn hours of July 4th. After passing through northern Minnesota during the morning, the derecho crossed into southern Ontario during the afternoon and continued trekking east across Canada during the evening. For several hours into the early overnight, the cluster of storms passed through less populated portions of Ontario and Quebec before reaching Montreal by early morning on July 5th. Even by the time the storms crossed back into the United States (in northern New England) during the predawn hours, it still was able to pack a punch, causing damage and resulting in another fatality.
