On Dec 18, 3:43*pm, wrote:
I think snow doesn't have any effect on AM transmitting.Too much ice
buildup though can, and sometimes does pull down towers and wires.
cuhulin

Critical Hours is a term for the period just after sunrise and just
before sunset, when a very few stations reduce power to keep from
interfering with other stations.

An example would be a station that is 50 kw day, 25 kw critical hours,
and 2.5 kw night.

When there is an emergency, a station can operate on its daytime
facility or, if directional, in non-directional mode to provide
community service. It is not permitted to run commercials.

A very bad blizzard, like a tornado, flood, hurricane or such event is
reason to consider such operations.