How do I keep my snake warm during a power outage

We lost power about 2 hours ago now (10pm) and probably won’t get it back until morning, we are unable to obtain a generator or run to the store for hand warmers. I did fill two water bottles with the last of our hot water and placed them inside the tank, but I doubt they will hold heat for much longer since there wasn’t much to begin with, I have also placed some paper towels over the mesh of the lid to keep some heat in.
My snake is housed in the basement, while it is currently 25f/-4c outside, our house is usually kept at 65f/18c, with a tank temperature of 85-70f/29-21c.
I was wondering if there’s anything else I could do to help keep him warm until our power comes back on or if he will be fine with what he has now until morning, thank you!

Maybe wrap the tank with blankets to insulate and maybe hold in what heat is there. Other than hot water or hand warmers that’s about all I got. Hope it goes well. I guess you could snuggle under the covers and keep your snake warm but body temps are probably to warm for that.

You can use reptile specific warmers, hand warmer style, used for shipping reptiles. They don't have fumes and do not get too hot.

DO NOT USE NORMAL HANDWARMERS meant for people. They can get way too hot and burn your snake or worse.

She will be okay down to 55-60F for a night as long as she isn't digesting.

Vented Styrofoam chest boxes can be good with those (reptile shipping) warmers used in conjunction. Make sure they are not directly touching the reptile and giving him/her spots away from them as well. If you don't have now, and it's lower than 60F or so in the house, try a pillow case and keeping her in bed with you. Tie a knot or zip tie the pillow case closed and keep her warm under the covers.

If you only have one snake, battery backups and car jumpers with an AC outlet can be used for keeping tank temps longer on your with your heating sources, or at least one.

Put the snake into a pillowcase. Put the pillowcase in a shallow plastic bin. Put the plastic bin under your covers with you at night.

The pillowcase + bin ensures that your snake can't escape, and the bin ensures that you won't roll over onto your snake while you sleep (or your cats and dogs won't step on it if they sleep in the bed), or if your snake pees you won't end up with soiled bedding.

Personally, if that was me, I'd put the snake into a cloth bag (snake bag or pillow case), secure it shut, & put that bag into my shirt (between 2 shirt layers, most likely).
We're about 98* and your snake will be between you for a heat source and the temperature-lowering room air. It's hard to do this if you have a bunch of snakes, but
with only one, this is what I'd do (& have done in an emergency). At night, the snake needs to be in a crush-proof container, as bcr229 already explained, so you don't
roll over on her in your sleep (& that HAS actually happened before & the snake was killed "mysteriously"-something very difficult for the owner to acknowledge).

Another option is to keep snake in a fairly SMALL insulated "cooler"-type lunch box (& put that inside a larger ice chest), & THEN use bottles of hot water to heat the smaller area inside. Be careful to wrap the hot water bottle(s) & the snake must be bagged as well...you don't want excessive heat either. But I went thru 3 days of an ice storm using hot water, bagged snakes in "ice chests"; I had to change the water in the bottles about every 8-9 hours, & they stayed adequately warm, & never got sick afterward.