Doing stuff is hard work. Is there a way I can just sit on my arse and gain virtue by appearing sympathetic?

I tell them like it is....."You need to evacuate" and "I hope you were smart enough to buy insurance" and "Good Luck with that" and "Mother Nature is trying to rid the earth of a parasitic species...."

You can physically help, you can donate and hope a decent amount of your donation actually goes towards relief, or you can sit on the wayside and realize you can't help everyone.

Do something.

I think the key is to be empathetic. Understand where they are and try to give comfort letting them know their difficulties are in your thoughts and you offer your shoulder, whether it is figuratively or literally.

"I feel for you"
"Best wishes"
My thoughts are with you and yours"

I recommend contributing to a secular charity. I've been impressed with the work done by the Foundation Beyond Belief, but there are others.
[foundationbeyondbelief.org]

Let me know how I can help.

Donations or volunteering, if that's an option

Donate, give blood, go help make hygiene kits, adopt a pet from your local shelter so they have room for animals being moved in from impacted areas.

My youngest uncle (who is more like a brother to me) is in Panama City. I spent a good deal of yesterday texting things like "you still alive, homie?" And "don't go getting bitches knocked up in the bathtub. Hurricane babies are not en vogue." (He was having a hurricane party, not luring in random refugees.) Humor is our thing and those messages showed I was thinking about him and hoping he was safe without resorting to trite bullshit. Different people would get different words based on our relationship.

In the big picture sense? I can't donate blood, so I usually find a charity on the ground and find out what they need. In this case I have a people on the ground and he is actually hosting people from the area who lost everything, so I'm just PayPal'ing money to him for now.

Doing something with your two hands is better than any prayer or condolences. Lend a helping hand, or if you can't do that because of distance, send money.

A hug is very comforting.

Well, as far as I can recall Prayer has NEVER once stopped a Natural/Man-made Disaster from occurring nor has it truly brought any comfort, ease, much needed supplies to the victims.
But, sheer, unbridled human generosity, kindness and concern has gone great distances to provide such reliefs to the victims.
For example, What were the first things to arrive after the massive earthquake and mudslides that struck Nepal a few years ago?
Answer cases of Bibles, no tents for sheltering the homeless, no blankets to help keep them warm, no foodstuffs or fresh water, just bibles, tons of them. Yes the pages would help the victims make small fires but you can't EAT bibles, nor can you find shelter under them from rain and cold.
Where Atheists and Agnostics give from their 'hearts' to those in dire need and expect nothing in return, the Faithfools give bibles and expect a Free Pass into Heaven.
So, if you can't give food, water, money, etc, search through your closets and find things such as clothing, blankets, etc, that you either no longer need/wear nor want, donate them in person or simply pay the freight to send them direct yourself, I did that when the Tsunami went across the Indian Ocean and I received quite a number of most unexpected letters thanking me from those who either received or were given my meagre donations.

Donating supplies, money and volunteering are probably the most useful and truly helpful ways to assist in this type of situation. Way better than prayers.

In the Words of Rickey Gervais “I feel so guilty. Everyone is sending their prayers but I only sent MONEY”

You show up with food, water, a chainsaw, gasoline,...

Send positive thoughts out to the universe.

Donate.