You might try these if you haven’t already. I use the ones for hands while I work and it’s made a huge difference. HotHands Insole Foot Warmers - Long Lasting Safe Natural Odorless Air Activated Warmers - Up to 9 Hours of Heat - 16 Pair https://www.amazon.com/dp/B001UQXAT6/ref=cm_sw_r_cp_tai_rlLgFbGJ4FKR5
Have you tried foot warmers? You have to activate them before you go out and then you can put them in your shoes. I use them for bike riding. Don’t know where you’re located (I’m in the EU and bought them at decathlon) but found this on amazon: https://www.amazon.com/HotHands-Insole-Foot-Warmers-Activated/dp/B001UQXAT6
It’s a pretty snug fit, but I’m sure you can squeeze some foot warmers in there if you wanted to
For the avoidance of doubt, it's 0°c out today, so unless the away dressing room had foot warmers available, there's probably a good reason for this implosion
I just got a box of these, haven't tried them yet but apparently they stay warm for 9 hours, they make them for the hands and feet:
https://smile.amazon.com/gp/product/B001UQXAT6/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
try the larger 'foot warmers' and large hand warmers. make sure they get some air to start, like 10 minutes.
https://www.amazon.com/HotHands-Insole-Foot-Warmers-Activated/dp/B001UQXAT6 https://www.amazon.com/HotHands-Body-Hand-Super-Warmers/dp/B0007ZF4Q8
are they wearing decent boots? rated for the super cold
https://www.lacrossefootwear.com/catalog/product/view/id/500/s/ice-king-10-brown-400g/category/448/
I think that's a dog, you can purchase foot warmers on amazon though
https://www.amazon.com/HotHands-Insole-Foot-Warmers-Activated/dp/B001UQXAT6
Gear is your friend if you got the cash. If you don't, then make sure you have a wind-proof outer layer like a cheap rain jacket (preferably breathable, but those don't come cheap), 2-3 insulating layers (preferably wool), and a moisture wicking base layer (preferably synthetic). You can also put over-sized nitrile gloves over your riding gloves to stop the wind chill. For your feet get some insole foot warmers, they're available offline at Wal-Mart. For cheap layers, Cyclegear's Warm'R stuff works very well (esp. the balaclava, glove liners, and long johns) and is windproof and somewhat breathable (slightly more than plastic, much less than Gore-Tex).
All those non-breathable cheap plastics will make you sweat underneath and you'll eventually get cold, but that beats freezing right from the start. Riding in 55 degrees can be quite comfortable if you make sure you insulate yourself from the wind chill, i.e. close any air access to exposed skin, and layer up.
For the really bad storms, I like Pajar boots. https://pajar.com/
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For boots that are just regular winter boots, I like anything Cole Haan offers that's waterproof. https://www.colehaan.com/womens-shoes-weatherproof
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Whatever you get, just stock up on the disposable heated insoles. I buy them in bulk every winter. Worth their weight in gold! https://www.amazon.com/HotHands-Insole-Foot-Warmers-Activated/dp/B001UQXAT6/ref=sr_1_4?ie=UTF8&qid=1539206796&sr=8-4&keywords=heated+insoles