No one likes to suddenly find cracks in their home, especially in the foundation. That type of damage can indicate serious problems that require expensive work. It won't do you any good to ignore the problem, so start investigating what might have happened to create such an alarming sight. Once you know what caused the crack, you can find a repair company for both the foundation and whatever caused the problem in the first place.
Unstable Soil and Erosion
Heavy rains can erode the soil around foundations and destabilize the ground, causing part of the foundation to bend and crack under the weight of the house. When no soil is bracing the foundation, then the weight of the house has nothing to oppose it as it bears down on the foundation.
You can also have unstable soil that was not properly prepared before the house foundation was constructed. This soil can shift, creating enough of a gap that the weight of the house bears down on that section of the foundation and cracks it. Soil can also become unstable as aggressive tree roots push through toward the house.
Frost heave is a condition in which the ground under something freezes, and then that frost expands, lifting the item on top of it. Frost heave can upend fence posts and harm trees, and it can even interfere with a house foundation. If frost heave caused the crack, the repair and mitigation process can take time; often the only avenues are to either replace the soil that can freeze with well-draining, coarse soil or improve the drainage in the existing soil around the foundation.
A Settling House
Cracks in the walls and foundation don't necessarily go all the way through; sometimes, they appear on the surface that you see, and that's it. This can happen as the house settles, and the foundation may still be in great shape. However, if you're not sure or if you have a bad feeling about the crack, it never hurts to have a foundation repair company take a look. They can confirm whether the crack is cosmetic or if there is a foundation problem that you need to address now.
You don't really want to mess with a foundation crack. Get it inspected, and if the crack is anything more than just cosmetic, arrange for repairs. For more info, contact a foundation repair contractor in your area.