It snowed in Red Rock and Mt. Charleston yesterday; however. with the temperatures skyrocketing (90's by next week) the snow will melt fast. Even by this weekend I think snow will not be an issue in Red Rock. The waterfalls should be flowing for the next few days.
I am not sure how much snow Charleston received. All the upper trails and peaks will have some snow. If the weather behaves, I believe the snow will melt by the end of this month.
Once the temperatures reach seventy or above, snakes will be active. Not to worry. First, there are only three venomous snakes around Las Vegas, all of them rattlesnakes. Secondly, I have only seen seven rattlesnakes in the past 13 years. The chance of running into a rattlesnakes is very low.