Premise: Earth has a magical cataclysm that pulls up new mountains, pushes down parts of landmasses, and generally reshapes Europe enough to make it unrecognizable (to the average person looking at a world map) in a period of weeks.
Problem: I'm trying to stick to more 'rational' magic that obeys most laws of physics (and with zero unexplained handwavium), and all the ways I can think of to do that much geographical change would probably end up kicking up so much dust and debris that it'd choke out the sun, killing plant life, and then everything that depends on plants.
Limitations: I want as few laws of physics broken as possible in the causal action, but for the result to be able to be explained entirely by physics. This means something like a magical push on tectonic plate ignoring strength/inertia/mass issues but with a result of making plates crash together and pucker into mountains like they would naturally do in response to that stimulus.
Goal: Make the geography/shape of Europe unrecognizable on a world map in a matter of 30 days, and have at least some of European humanity survive (while still living in Europe).
Can you think of any plausible, semi-rational ways to achieve this end?