by Bill Cummings » Wed Jan 12, 2022 7:04 pm
I’ve flown over many inland lakes by boat towing.
In the 80’s Minnesota Power and Light Company
released boiler cooling water back into Colby Lake
near Hoyt Lakes Minnesota. This lake stayed ice free
all winter long. The Minnesota Environmental Protection
agency, years later, made the company use cooling ponds
before returning the water to the lake.
Every winter afternoon hundreds of seagulls would
thermal up off the lake and fly 45 miles back to Lake Superior
(One of the five Great Lakes). Superior would also
stay open most all winters.
I would thermal elsewhere over shallow swamps up
until a half an hour before sunset during the summer.
Near sunset the ground would cool sooner than the
shallow swamps. About an hour and a half before sun-
set I would switch from land thermals to swamp water
thermals.
Thermals crossing over water reflect a darker
wind print than the surrounding water.
It’s just the opposite for wheat fields. The
wind print in a wheat field is a lighter
color. Like a spot light moving across the field of wheat.
Water thermal wind prints may have a calmer lighter
circle inside the darker wind print if the thermal is strong.
Ocean wave soaring birds can ride the lift of the moving
hill (wave) that pushes the air up. Instead of the air moving,
the hill/wave moves producing the same ridge lift.
Dynamic Soaring is another way birds glide without flapping.
I should do well over water because my 2004 Sport 2 flaps
all the time.
Home
