What did you think about last evening’s thunderstorms? You might ask what storms?  Well residents of northeastern New Brunswick can tell you it was wild in their area!  The cold front started to push down across the north late in the day.  The front – the mechanism that created the lift – was travelling in a dry slot and that made for some very impressive photos.  Cumulonimbus clouds are where thunderstorms are born, but they are often embedded and we don’t always seem them.  Last evening, you could see that cloud and more.

Judging from Facebook comments, many of you experienced quite a display of lightning.  Those cumulonimbus clouds with the flat or anvil shaped tops are mature clouds and can put on quite a show.

Yesterday, a less common cloud was spotted at the base of a few of the more intense thunderstorm cells: a shelf cloud!

A shelf cloud is a low, horizontal wedge-shaped cloud attached to the base of the parent cloud or cumulonimbus.

Here’s how it forms:

Cool, sinking air from a storm cloud’s downdraft spreads out ahead of the cold front.   

As the cool air lifts the warm moist air, water condenses creating a cloud which often rolls with the different winds above and below.  The leading edge is called a gust front and the shelf cloud forms in this gust front.

A sharp, strong gust front will cause the lowest part of the leading edge of a shelf cloud to be ragged. The line of wispy, torn cloud is called scud. In extreme cases, there will be funnels along the edge of twisting masses of scud.

There was some damage last night over parts of the Acadian Peninsula, but thankfully, no one was seriously injured. 

It’s one thing to admire the power of Mother Nature, but remember to always do so safely!



Chief Meteorologist

Cindy Day