Freeze and frost, what's the difference?

(WAND Weather) — Central Illinois will see its first frost and freeze of the season Tuesday night into Wednesday morning. Western portions of our viewing area are currently under a Freeze Warning; while the eastern half is placed with a Frost Advisory.

Frost forms when the air temperature drops into the mid 30s; under clear skies and light to calm winds. Air temperature is measured a few feet above the ground but since cold air sinks, this will allow the ground temperature to cool even further into the low 30s.

The moisture in the air which is water vapor will freeze when reaching the surface forming ice crystals known as frost. The process of a gas forming into a solid without becoming a liquid is known as deposition (water vapor to ice). White frost or hoarfrost tends to have branchlike patterns similar to a tree.

A freeze occurs when the air temperature gets so cold that little to no frost occurs. This is known as a black frost as leaves blacken from the cell damage of the water freezing.

The 4 P's are a common reminder of what to do during freeze and frost which is: protect plants, pets, pipes and people.

Plants and sensitive vegetation should either be covered up or brought inside. Pets should be brought inside just like in the heat, while pipes should be covered or set to drip water from the spigot to avoid bursting. Lastly, people should layer up while being outside and have a way to properly heat inside the home while also checking on others.

The National Weather Service issues three alerts regarding freeze and frost.

A Frost Advisory is provided when temperatures are forecasted to fall between 33°- 36°. A Freeze Watch is issued within 24-36 hours of the potential of temperatures falling between 32° and under. A Freeze Warning occurs when temperatures are expected to fall 32° and under. The Freeze Warning signals the end of the growing season during the fall; while in the spring, it means that new crops can be damaged after the start of the growing season.