Mosfet Snubber with Inductive Load
In these circumstances I'd use a zener diode across Q1 - then there is no doubt that the maximum voltage that is imposed by the relay coil (when it is open circuited) is limited to the zener voltage thus protecting the transistor. If the transistor AMR (absolute maximum rating) was 60 volts, then choose a zener that's rated at two-thirds of 60V i.e. 40 volts (a 39 volt zener will do just fine).

The problem with a snubber is that when the MOSFET open-circuits, 100mA will flow thru the 100 ohm resistor and charge the capacitor up rapidly to some voltage that is hard to determine - if you knew the inductance of the relay coil (and hence the stored energy) this could be calculated but I guess you don't or you would have said.