I'd get the holes covered with large sheets of heavy plastic (well secured) right away (get off the internet now!). Don't do any work you're not comfortable doing (its not worth serious injury). After 911, Katrina, and the August 2003 blackout the message we get in the U.S. is to plan on being "on your own" for the first 3 days after a regional incident.
I kinda expected some help today, but realize now that was unrealistic. However, the SES (State Emergency Service) just showed up. Staffed by volunteers... wow, I'm impressed, it's 10:30 PM here, and these guys have been going all day around here. One asked about my pipecleaner dipoles and is interested in building a Seas kit.. perhaps he will be a new AC member

Anyway, they reckon there's not much they can do about the roof, the hole is too big to cover with tarps -- it will just fill with water and cave in anyway. This roof is very steep and high off the ground -- no-one is getting up on the outside until it dries out. Regardless, the neighbour behind me is going to help me tomorrow to see what we can cook up to help keep the water out of the house.
Yep, climate here is pretty mild overall. I like that bit

This area used to be a lot of holiday homes, I don't think construction quality was all that high on the list of priorities. Still, the roof has been fine in 120 kph winds for the last 30+ years.