A large body of research from around the globe reports that same-day barometric pressure and temperature are related to bone and muscle pain ratings made by humans. This is as (perhaps even more) apropos for bony fresh- and salt-water fish, and it may be particularly true for freshwater species living in shallow, constricted lakes and ponds.
I fished for salmonids in dam pools in Wisconsin for 15 consecutive spring and fall spawn runs, and in deep pools in Wisconsin and Michigan Lake-run Rivers as well as in Illinois power-plant water discharge channels in winter. During these excursions I recorded field notes, and spoke with anglers I met regarding their thoughts on any possible relationship between weather and fishing. My anecdotal findings are consistent with some reports on this subject which I’ve read. In my area, in dam and river pools, rivers and lakes (large and small), I found the following to be generally accurate:
• The hours just before a cold front hits is often relatively good fishing, and is sometimes outstanding fishing for older/larger fish populations which have familiarity with their physical responses that occur in response to changes in barometric pressure and temperature.
• The first day that a cold front hits the fish won’t eat, and won’t move much.
• The second day of stable weather, the fish will move about a bit and nibble at bait, but fishing is slow.
• On the third day of stable weather, once the water temperature elevates by at least one degree Fahrenheit, the fish feed again—sometimes voraciously.
Probably everyone has heard the adage, “rules are made to be broken.” In the present case, as described below, a more appropriate adage might be, “some rules may break you!”
It was October in Chicago, so fish were staging for the fall spawn run. The sun was coming up, and a cold front was approaching—fish are around and they are experienced, so there may be a bite happening as soon as the surface water temperature picks up a little bit. I grabbed my casting rod and pre-packed backpack, hopped on my mountain bike, and headed for the Montrose Park Fishing Pier. Once there I headed for the northeast corner tip, where the best fishing was usually happening.
I started casting my spoon, but the appearance of the horizon north of me was alarming. Medium-dark grey (not black) clouds hovered in a “wafer” over the Lake–like a fog, but fog is white. I noticed some irregularity in the movement of the surface clouds on the horizon. A few moments later a feeling of panic hit me as I realized that what I was seeing was a stunningly wide wave—going from near the shore and heading out into deeper water—heading right for me!
What should I do? If I make a run for it the wave will inundate me from behind, and sweep me off of the pier: in addition to losing my gear and ride, I might lose my life! I chose to hang onto the inside (facing the wave) of the metal rope fence in the middle of the pier walkway. I huddled face-first against the fence, and braced myself, my bike, and my equipment (backpack and rod).
The wave hit, and thankfully it only cleared the pier by a foot at most—yet it hit me with a stunning amount of force due to its speed. Unlike a tsunami, which is a giant block of water (wide, tall and deep), the storm-surge wave I encountered was wide, short, and skinny. The wave swept over the pier and kept going. No other wave was visible. I bungie-corded my backpack on the bike, grabbed the rod, and rode home at high speed aided by the wind at my back.
If anyone wishes to fish an approaching cold-front, I recommend caution if in an exposed position on a body of water sufficiently large (or long) to produce large straight-line-storm wind-generated waves.
Chicago Mini Tsunami
Paul R. Yarnold, Ph.D.
January 2, 2021