What is a frost quake and where do they occur?
Have you ever woken up to a booming noise in the middle of a frigid winter night? You probably heard a frost quake. AccuWeather's Emmy Victor explains the winter phenomenon.
What Is A Frost Quake?
Frost quakes are seismic events that are weather-related. A seismic event is any activity that causes vibrations within the earth, particularly its crust. Frost quakes are naturally-occurring phenomena caused by the freezing and expansion of water deep within the earth's crust, which results in the cracking of the ground, rock, etc., in the vicinity of the frozen water.
What Causes Frost Quakes to Occur?
Frost quakes, formally known as cryoseism, occur when temperatures that have dropped below freezing (measured in Fahrenheit, not Celsius) affect water that is trapped underground. As the water rapidly freezes and expands, the ground around it is shifted. The sudden expansion and movement can result in the ground becoming cracked. Along with subzero temperatures quickly freezing the underground water, four main factors come into play in the formation and occurrence of frost quakes:
Deeply Saturated Soil
For a frost quake to occur, there must be sufficient water present, and this water must be located deep within the ground. This happens most frequently in areas where there has been a great deal of precipitation in some form in a relatively short period. The precipitation can be in the form of rain, sleet, or a mixture of wet weather conditions that have saturated the ground saturated deep down. The severity of the cracking of the soil depends on the amount of water present.
Quick-Freeze Regions Experience Frequent Frost Quakes
Frost is formed from molecules of water that are present in the air when temperatures plummet quickly to subzero levels. The presence of these two weather conditions is necessary for frost quakes to occur.
Photo captured frost quake evidence in the Prospect, Connecticut, area on Thursday, Jan. 24, 2019. (Twitter/@kthellm)
Temperatures Drop to Below Zero Rapidly
When temperatures are at the freezing point, water located even deep underground can begin to freeze. When the temperature drops rapidly, within approximately 12 to 48 hours, water that has collected below the surface of the ground freezes solid and expands quickly. This change cracks the ground, including rock, around the solid ice formation.
Only A Small Amount of Snow Is Present
An abundance of snow will prevent frost quakes from occurring. This is because snow acts as a sort of insulation when it is present in sufficient amounts. The presence of as little as six inches of snow is enough to keep the freezing air from affecting the ground when the temperature drops rapidly, thus preventing frost quakes from taking place.
For these reasons, frost quakes occur only in areas where the conditions are just right. Vibrations from frost quakes are not felt above ground like those caused by earthquakes, but they do produce rather loud booming sounds. These booms have been reported to be loud enough to wake people up from a deep sleep in nearby homes in some instances. The vibrations from frost quakes are often strong enough to be measured and recorded on a seismometer, also known as a seismograph, which is a device used to measure ground movement during events like earthquakes, volcanic eruptions, etc.
Photo by Edoardo Denunzio
Where Can Frost Quakes Be Experienced?
Since frost quakes do not cause damage, and since it is virtually impossible to predict when and where they will occur, it takes more luck than skill to experience them. To date, no reliable means of forecasting frost quakes has been developed. It is possible to experience the sounds produced by frost quakes and, in some instances, see the cracks and fissures caused by this cold weather phenomenon along the surface of the ground. If you are in an area where the weather conditions are optimal, you may be lucky enough to be close by when they occur.
Frost quakes are known to commonly occur in Alaska, Canada, the northeastern United States, Iceland, and other geographic locations where the necessary weather conditions frequently manifest.
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