Why Pipes Burst
When water freezes, it expands. That's why a can of soda explodes if it's put into a freezer to chill quickly and forgotten. When water freezes in a pipe, it also expands the same way. If it expands enough, the pipe bursts, water escapes and serious damage results.
Surprisingly, ice forming in a pipe does not typically cause a break where the ice blockage occurs. It's not the radial expansion of ice against the wall of the pipe that causes the break. Rather, following a complete ice blockage in a pipe, continued freezing and expansion inside the pipe causes water pressure to increase downstream. Between the ice blockage and a closed faucet at the end. It's this increase in water pressure that leads to pipe failure. Usually the pipe bursts where little or no ice has formed. Upstream from the ice blockage the water can always retreat back towards its source, so there is no pressure build-up to cause a break. Water has to freeze for ice blockages to occur. Pipes that are adequately protected along their entire length by placement within the building's insulation, insulation on the pipe itself, or heating, are safe.
Call SERVPRO of Helena & Great Falls if you experience a broken pipe in your Helena or Great Falls home (406) 458-6008.