This isn't a backpacking story, but rather MTBing, but illustrates what SKLund writes above. It was April and I was riding the White Rim with some friends. Got to Potato Bottom, where we had a reservation for the night, when it started pouring. We quickly set up our tents then hopped into our support vehicle (an old Jeep Cherokee) to try to sit it out. My friends were geologists, except one, who was a nurse, and they all started drinking beer, which I've been told is restorative for geology types, as they're an alcohol-based life form. But I'm not much of a drinker and got tired of sitting there and hiked to the top of a nearby mesa and found a whole field of Moki Marbles, but that's another story.
It was getting on to dusk (and much colder) when we saw a vehicle sliding its way down the big hill there. By the time we'd set up a betting pool on whether they would make it down or go off the edge, they came driving into camp. It was a ranger there to inform us they were shutting down the road and to stay at this camp until further notice, even though we had reservations for the next two nights at Murphy's Hogback and Gooseberry. By then it was lightly snowing and darn cold. The White Rim is very sandy but also has a lot of clay in places where one can sink up to their axles, especially along the Green.
We hunkered down in the Jeep for a bit longer, then hunger overcame us, so we built a small fire and started making spaghetti. The nice thing about mountain biking with support is it's kind of like rafting - you can bring all kinds of good food and junk (like cases of beer, if you're into geology). We finally went to bed, tired.
We spent the next day again hunkered down as it poured rain, though it had started out like it was going to clear off. FInally, it was almost totally dark when we saw a half-dozen Tolkeinesque forms coming in the gloaming and pushing what appeared to be bike-shaped mud things with gummed-up wheels.
It was the group riding the opposite way from us who had reserved Potato Bottom for that night. I have no idea why they had continued after the ranger said not to, but here they came. Their support vehicle was nowhere to be found. These poor people were in various stages of hypothermia, chattering teeth and all that, most wearing shorts and pathetic nylon wind jackets and soaking wet. We got the remainder of the wood we'd brought and built a big fire (probably illegal), got them next to it, while our nurse friend made them drink hot tea. We put them in the Jeep for awhile with the heater on, but worried about running out of gas, as we'd already sat in it a bunch with the engine running.
Well, finally it stopped snowing/raining, we got them into our extra dry clothes, everyone warmed up, and we all doubled up with what supplies we had and made it through the night, though it was pretty uncomfortable. We bid them farewell the next day, when a different ranger returned and told us we could continue.
We had to stay on schedule, which meant riding all the way to Gooseberry, but we were just glad we were there for those other riders, as there's no way they would've made it through the night. We passed their support vehicle stuck in the mud and managed to pull him out. Ironically, the group we'd helped told us while sitting around the fire that they actually had all kinds of rain and cold-weather gear, but it was in their support vehicle.
TL-DR: Helped people with hypothermia.