Link 1: #uksnow Map - See where it is snowing in the UK right now!

This site has already been mentioned by @JJonas in this post:

Link 2: Snow!



Link 3: Snowbird

The Snowtweets Project provides a way for people interested in snow measurements to quickly broadcast their own snow depth measurements to the web. These data are then picked up by our database and mapped in near real time. We are especially interested in using web-based digital technologies to map snow depth data; currently, the project uses the micro-blogging site Twitter as its data broadcasting scheme.

Visualization of data is a key aspect of the project. To view the snow depth measurements (or tweets), we have developed a data visualization tool called Snowbird that lets you explore the reported snow depths around the globe. You can also click on the navigation link (visualization) at the top of the page that will take you there. The viewer shows where the reports are located and how much snow there is at each reported site.

We have also developed a near real-time satellite data feed so you can see how the tweets compare with the satellite view. Snowbird will allow you to toggle real-time satellite NASA MODIS data which gives snow cover extent. You can also look at some historical maps for north America...
The Snowtweets map opens with the whole world visible. Zoomed to the UK and selecting OpenStreetMap as the map view: