Fall colors slowly begin to arrive along North Shore
As the days grow shorter and a subtle chill creeps into the air, Minnesota’s North Shore undergoes a colorful transformation.
During this time, the North Shore becomes a haven for those seeking to explore hiking trails and endless back roads to bask in the vibrant hues of the fall foliage. Fall colors in Minnesota typically peak in mid-to-late-September through mid-October, starting in the northernmost part of the state and working southward.
Many factors play into the timing and brilliance of the fall color season in Minnesota, including day length, temperatures, and rainfall.
“As day length decreases, deciduous trees stop making chlorophyll, which is the green pigment crucial for photosynthesis,” said Brian Schwingle, a forest health specialist with the Minnesota Department of Natural Resources, in a recent educational webinar.
While various tree species will change colors at different times, Schwingle said, “The timing of fall color is primarily driven by day length and then by genetics.”
An early fall frost in the upper Midwest can also play a role in the vibrancy and length of fall colors. A frost can “halt the physiological fall color process in its tracks,” Schwingle said. “We don’t want an early hard freeze.”
Cory Rothstein, a meteorologist with the National Weather Service, told WTIP on Sept. 11 that a cold spell with the potential for frost will likely arrive late Tuesday. Sept. 12 and into the early morning hours of Wednesday, Sept. 13.
“Looking at some potential for frost, especially for inland areas,” Rothstein said. “We’re looking at temperatures getting down into the mid-30s and even some localized pockets of low 30s.”
The National Weather Service said it is not unusual for frost and mid-30s temperatures to arrive at this time of the year. “It’s not completely unusual to see patchy frost this time of year,” he said. “But a little early in Sept. compared to what we would typically see.”
Fortunately, Rothstein said, the frost conditions are isolated to Tuesday and Wednesday, as temperatures will resume to 60s and even 70s in some inland areas later in the week.
As of Sept. 11, the Minnesota DNR’s Fall Color Finder shows that the North Shore and parts of the Arrowhead region are at 0-10% of peak fall colors. At the same time, areas surrounding Duluth, Ely, and part of the BWCA have reached 10-25%.
The Minnesota DNR provided a fall color update in a recent educational webinar. Audio clips from the webinar discussing the science of fall colors and the current outlook are below.
Kalli Hawkins September 11, 2023
