That storage compartment is usually quite small, but you could squeeze in, say, an AMK survival shelter and some other goodies. Many snow mobiles will have a luggage rack, but those used for joy rides typically won't have them.

In my opinion, survival in winter typically requires gear with bulk about the size of a day pack. (Shelter, showel, extra clothes, some way to melt snow, preferably some ground sheet). With a little ingenuity, that bulk can be distributed all over the snowmobile - but you have to be willing to modify it. Such as making additional anchor points and tie-downs here and there.