The first hard freeze always catches somebody off guard
If you've lived around Republic for more than a winter or two, you know how this goes. The week is mild, maybe even warm enough for a jacket to feel like too much, and then a cold front drops out of the north overnight and the temperature falls thirty degrees before you wake up. That swing is normal for southwest Missouri. It is also exactly the kind of thing that catches pipes off guard, because a house that has not had to defend itself against real cold yet suddenly has to do it all at once.
Right now, if you're noticing a weak trickle at one faucet, a knocking sound in a wall, or a spot under the kitchen sink that feels colder than the rest of the room, pay attention. Those are the early tells. They show up before anything actually bursts, and they usually show up in the same handful of places every single time.
Why some pipes go first
Not every pipe in your house is equally exposed. The ones that freeze first are almost always the ones running through unheated or under-insulated space: crawl spaces, garages, and exterior walls on the north or west side of the house, which take the brunt of the wind here. A lot of homes in Republic, especially the ranch-style houses built from the 60s through the 80s that make up so much of the older neighborhoods, were built with crawl space foundations rather than full basements. That crawl space is often the weak point. If the vents haven't been closed for winter or the insulation under the floor has settled and thinned out over the decades, the pipes running along those floor joists are sitting in air that's not much warmer than outside.
Kitchen and bathroom lines on exterior walls are the other repeat offender. Builders sometimes ran supply lines through outside walls to keep them close to fixtures, and in an older home that wall cavity may have little to no insulation behind the pipe itself. A garage with a water line for a washer or a hose bib is another spot that freezes early, especially if the garage door gets left open even for a few minutes on a cold morning.
More on this from Which Pipes Freeze First In An Ozarks Cold Snap.
What you can check yourself
Before a cold snap hits, or the first time you feel one coming, it's worth spending twenty minutes doing a walk-through. Open the cabinet doors under sinks that sit on exterior walls so warm room air can reach the pipes. If you have a crawl space, go take a look at the vents and close any that are open. Check that there isn't a gap where a pipe passes through the floor or a wall where cold air is getting a straight shot at it. Foam pipe insulation sleeves are cheap and easy to fit yourself on any exposed line you can reach, and they make a real difference on a crawl space or garage line.
During the cold snap itself, letting a faucet run at a slow trickle on the coldest nights, especially at a fixture you know is on an exterior wall, keeps water moving and makes it much harder for ice to form. If you're leaving the house for a stretch of days in January, don't turn the heat off or down low. Keeping the thermostat at a normal setting costs you a bit more on the gas or electric bill, but it costs a lot less than what follows a burst pipe.
When it's already too late to just watch and wait
If you turn on a faucet and get nothing at all, not even a trickle, that's different from low pressure. No flow at all usually means a freeze has already formed a blockage somewhere between the meter and that fixture. At that point, don't reach for an open flame or anything that could scorch a pipe or start a fire in a wall cavity. A hair dryer on a visible, accessible section of pipe is about as far as a homeowner should go, and only if you can see the pipe directly, not if it's buried in a wall or under the floor.
If you can't get to the frozen section, if water is already leaking or dripping somewhere it shouldn't, or if you hear a pipe that has clearly split, that's the point to shut off the main water valve and call someone who does pipe repair for a living. A cracked or burst pipe inside a wall or under a slab isn't a project to troubleshoot on your own, and every hour it sits there while you decide what to do is an hour more water is finding its way into insulation, drywall, or flooring.
After the thaw, don't assume everything is fine
Once temperatures climb back up, which around here can happen within days, keep an eye on ceilings, walls, and floors near the pipes you were worried about. A pipe can crack from ice expansion and not leak until the ice inside it melts and water has somewhere to go. A stain on a ceiling below a bathroom, a soft spot in flooring, or a musty smell in a crawl space access a week after a freeze is worth checking out, and it's the kind of thing that's much cheaper to deal with early than after it's had a month to spread.