How to get rid of the snow?

[waterboy 0]

I have been playing this one city up to the 800th year, a city which is all very high altitude and surrounded by even higher mountains, trying to achieve a Denver type of feel.  Just today I went to go and load the game up and the entire city was covered in a thick, white blanket.  I noticed that, in the bottom of a deep canyon which runs through the city, during the summer months you can see the snow residing back, but not enough to ever uncover the main, high altitude ground of the city.  How can I get rid of the snow that covers my city and makes it unplayable?

 

****NOTE: I do not use any types of mods.  This can not be the effect of any type of weather or snow mod, so I'm really puzzled on how to get rid of it.

[DuskTrooper 314]

It is a Christmas Easter egg. Just..wait until tomorrow, and it shall go away.