Memorable June tropical storms

 

Allison's rainfall, June 2001 (Source: NOAA)

The Atlantic hurricane season runs from June 1 - November 30. June and November are typically the quietest months of the season when atmospheric and environmental conditions are the least favorable for development. However, June has produced several destructive tropical storms and hurricanes, as described below.

Chris (2012): The Atlantic hurricane season got off to a fast start in 2012 with four named storms by the end of June. Chris became the first hurricane of the season and was a Category 1 at peak intensity with 85 mph sustained winds. Chris meandered around the northern Atlantic and had no direct impacts on land while a named storm. It was noteworthy for being the farthest north any June hurricane has developed in the Atlantic. According to NOAA, Hurricane Chris “developed from a baroclinic low that formed along a cold front near Bermuda.” That means this storm relied on a strong air temperature gradient to help it develop since sea surface temperatures were only in the low 70s, well below the 80-degree threshold a tropical system normally requires to develop.

Allison (2001): Tropical Storm Allison had the impressive distinction of being the first storm to have its name retired by the World Meteorological Organization without reaching hurricane intensity. Tropical storm and hurricane names are retired for being damaging and/or deadly (e.g., Katrina, Andrew or Michael). What made Allison unique wasn’t its intensity, but its longevity.  After making landfall in Texas, its remnants lingered for days and caused devastating flooding.  Allison caused an estimated $15.9 billion in damages (2024 dollars) and remains one of only two tropical storms on the list of costliest tropical systems on record in the United States, according to the National Hurricane Center.

Bonnie (1986): Hurricane Bonnie was a rare June hurricane that developed in the Gulf of Mexico. It made landfall near the Texas/Louisiana border at peak intensity as a Category 1 storm with 85 mph sustained winds. Bonnie brought flooding rainfall to much of the U.S. Gulf Coast region. This was the last hurricane to make landfall in the United States during the month of June.

Agnes (1972): Agnes became a minimal hurricane over the eastern Gulf of Mexico on June 18, but isn’t remembered for that. As a weaker tropical storm, Agnes menaced much of the Mid-Atlantic and northeastern United States where its remnants caused widespread flooding. Multiple June rainfall records were set from Virginia to New York, including DC’s wettest June day (6.11” on June 21, 1972). Agnes subsequently had its name retired. Agnes and the flooding its remnants produced led to over 100 deaths, according to the National Weather Service.

Hurricane intensity is ranked on the Saffir-Simpson Hurricane Wind Scale, with a Category 1 being a “minimal” hurricane with sustained winds speeds of 74 to 95 mph. A hurricane becomes “major” when sustained winds reach 111/+ mph, making it a Category 3. The strongest hurricanes are Category 5’s, with sustained winds of at least 157 mph.