How can you tell the difference between types of wintry precipitation? Here's an explanation.
By News 12 Meteorologist Allan Nosoff
The News 12 Storm Watch Team has been tracking wintry precipitation in the forecast. Hearing phrases from ‘icy mix’ to ‘wet snow’ can make things confusing at times. What kinds of wintry precipitation are there, and how can someone tell the difference between them? This is what you need to know:
Precipitation develops in the clouds as snowflakes. Once the snowflakes begin to fall, the temperature of the air between the cloud and the ground dictates what kind of precipitation reaches the ground.
If the air between the cloud and the ground is warm, above 32°, as well as the ground itself, the snowflake melts into raindrops and falls as rain.
If the air between the cloud and the ground is above 32°, while the ground itself is cold, below 32°, the raindrops freeze on contact, becoming freezing rain.
Freezing rain is the most dangerous kind of wintry precipitation, as it only takes a glaze of ice to cause significant impacts on untreated roads and sidewalks. A glaze of ice from freezing rain may just look wet on the roads, but in reality is a frozen and dangerously slick surface. If the freezing rain accumulates (more than 0.1”), power outages and downed tree limbs are possible.
The difference between freezing rain and sleet is that there is more air above the ground that is cold, below 32°. Snowflakes begin to partially melt, and refreeze in the air before reaching the ground. This partial snowflake/frozen raindrop combination is known as sleet.
There is a very common misconception when it comes to winter precipitation: oh hail no! People tend to confuse sleet and hail while they actually have two completely different processes of formation and occur in different seasons.
Hail forms at the top of a thunderstorm, growing in size as other ice crystals and raindrops freeze on them. This process happens while strong winds inside the thunderstorm keep the hail suspended in the clouds. When the hailstones become too heavy, gravity pulls them down to the ground.
If the air from the cloud to the ground is below 32° the entire way, the snowflake reaches the ground and snow occurs.
Snowflakes are wetter and heavier at or around 32°, lighter and fluffier with temperatures below 30°. The wet and heavy nature of the wintry precipitation is why sleet pellets accumulate more compactly than wet snowflakes, and fluffy flakes stack up fairly quickly.
The News 12 Storm Watch Team will continue to keep you updated on what kind of wintry precipitation to expect as the next storm system approaches the area.