Something to do with weather?
No idea, but looking at a map of aquifers, I realize that I'm a little off on my orientation. I still suspect climate related.
Red is more/less vs blue?
Yellow is absence of red or blue
Looks like something to do with wind or rain...change over time? Blue least change, red most?
Can people see that change easily or is the rate of change such that it usually escapes our notice until lots of time has passed?It is change over time of something, yes.
Can people see that change easily or is the rate of change such that it usually escapes our notice until lots of time has passed?
Averate Temps in Winter?
No, but I would expect that such a map and this map would look similar.
Future Canadian expansion plans into the USA?