Journal Pioneer

Can science explain something so beautiful?

- CINDY DAY weathermai­l@weatherbyd­ay.ca @CindyDayWe­ather Cindy Day is SaltWire Network’s ChieI MeteoroloJ­ist.

What talented artist was behind the stunning image on the old church roof?

Michal King was in awe at the frosty scene he saw on the roof across the street, “as if a giant paintbrush had been at work during the night.”

Yes, Mother Nature is quite an artist.

When it comes to the marvels of weather, it can be a little like baking a cake: you need all the right ingredient­s for things to turn out! Hours before Michal snapped the photo, a cloudless sky, windless night and relatively high humidity came together to produce hoar frost on that church hall roof in Dartmouth, N.S. A few hours after sunrise, the shadow of the leafless tree had prevented the sun from melting off the hoar frost!

Hoar frost. It doesn’t sound pretty but that’s what it was. Hoar frost is a deposit of ice crystals on objects – most often vegetation – exposed to the air. It’s formed by direct condensati­on of water vapour to ice. The key for hoar frost to form is there must be an influx of moisture into the region while the air remains sufficient­ly cold. You’re no doubt familiar with the term “dew point.” In the warmer months, it’s the temperatur­e to which an air mass must be cooled to reach its condensati­on point. Frost point is its winter cousin and results in hoar frost.

Hoar frost can be so thick that it can look like snow. Hoar frost shouldn’t be confused with rime, which occurs when freezing fog forms a solid layer of ice. This might help: from gas to solid, it’s hoar frost; from liquid to solid, it’s rime.

People often ask me where the term comes from. The adjective “hoar” or “har” goes back to Old English and means “greyish white; grey or grey-haired with age.”

Hoar frost is very photogenic! Thanks Michal.

 ??  ?? What a siJht Michal couldn’t belieYe his eyes when he looked out his window one morninJ. +e says it was an astonishin­J pattern oI tree branches as iI a Jiant paintbrush had been at work durinJ the niJht. Michal liYes directly across Irom historic Christ Church in downtown Dartmouth N.S.
What a siJht Michal couldn’t belieYe his eyes when he looked out his window one morninJ. +e says it was an astonishin­J pattern oI tree branches as iI a Jiant paintbrush had been at work durinJ the niJht. Michal liYes directly across Irom historic Christ Church in downtown Dartmouth N.S.
 ??  ??

Newspapers in English

Newspapers from Canada