UPDATE: How could I have forgotten bomb cyclone? We’re in the middle of one right now!
Spoiler: not exactly fun
I learned two three new weather terms this year. Learning things is fun! Learning these terms was less fun, since they affected me in somewhat unpleasant ways.
It’s possible I’ve heard these terms before, but either forgot them or they never registered.
Here they are!
HEAT DOME
What is a heat dome? Here’s the definition from NOAA (read a more detailed explanation at the link):
A heat dome occurs when the atmosphere traps hot ocean air like a lid or cap.
We had a heat dome in late June/early July. At its peak, the temperature here in New Westminster got up to 42 degrees Celsius. As I recounted at the time, this is quite warm indeed, particularly for this area where a summer high might be nearly 20 degrees cooler. I know what a heat dome is now, but feel no better with the knowledge, as I wonder if Summer 2022 will bring more domes.
ATMOSPHERIC RIVER
NOAA also has a handy explanation of these:
Atmospheric rivers are relatively long, narrow regions in the atmosphere – like rivers in the sky – that transport most of the water vapor outside of the tropics. These columns of vapor move with the weather, carrying an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi River. When the atmospheric rivers make landfall, they often release this water vapor in the form of rain or snow.
The NOAA article talks about benefits of some atmospheric rivers, like increased snowpack, but in local context they have always meant rain and a whole lot of it. When we got one of these rivers flowing overhead recently, the Brunette River rose higher than I’d ever seen–high enough for those signs along the river trail warning about sudden changes in water flow suddenly resonating.
See the bit of river at the bottom of the photo? That’s normally not underwater. If it had gotten a little higher, the river would have started spilling out over its banks.
So far I do not like atmospheric rivers, although they do have the advantage over heat domes of not making your face feel like it’s on fire.
BOMB CYCLONE
This one I just heard about in the last few days and as I update this post early on the morning of October 25, one is hammering the south coast, leading to power outages, cancelled ferry sailings and more.
Definition from this NBC News story:
A bomb cyclone is simply a storm that intensifies very rapidly. Bomb cyclones form when air near Earth’s surface rises quickly in the atmosphere, triggering a sudden drop in barometric pressure — at least 24 millibars within 24 hours.
I love the use of the word “simply” there, as it goes on:
As the air rises, wind spirals in at the base of the storm. As long as the air continues to rise at the top of the storm faster than it can be replaced at the bottom, barometric pressure will continue to drop. As with a hurricane, lower air pressure yields a stronger storm.
Like a hurricane. No biggie! And maybe happens once a year. And we’re only a month into fall, when the window for these things is basically now through early spring. Woo.
