I had friends tbat li ed on Badger Rd in North Pole, a notorious cold spot. It was not unusual for them to be able to drop down to the Chena River behind their house and it be 20 degrees colder than the house thermometer. Vertical difference of perhaps 15'.

If you take the time it takes, it takes less time.
--Pat Parelli

American by birth; Alaskan by choice.
--ironbender