Village of Lytton, B.C., evacuated as mayor says 'the whole town is on fire' (opens in new tab)

When I look up pictures of Arizona I see cacti and deserts. Lytton is hot but it’s a lot of forests and lakes. Would an equivalent be Arizona getting a severe Canadian winter with 1-2 weeks of -40 ?

On 10 July 1913, temperatures at the aptly named Furnace Creek area in the California desert reached a blistering 56.7°C (134.1°F).

https://www.sciencemag.org/news/2021/05/move-over-death-vall....

No. That was the temperature of the damn air. It's nuts.

> Are you sure you’re not quoting the…

Yes.

https://climate.weather.gc.ca/climate_data/daily_data_e.html...

It's air temperature: https://twitter.com/ECCCWeatherBC/status/1410017678216024067

yikes... been through weather like that in Australia a couple of times. but yeah I can't imagine houses and people (and animals) in Canada are accustomed or designed to handling anywhere near that.

From The Article:

"It took, like, a whole 15 minutes from the first sign of smoke to, all of a sudden, there being fire everywhere."

They didn't give up. They got chased out without notice. By fire.

> But high heat which approaches the wet bulb temperature is just stressful on the body.

Note that "wet-bulb temperature" (WBT) is not a specific value for temperature, it is a way of measuring temperature. You can cave a WBT of 0C, or a WBT of 35C. WBT is the temperature shown by a thermometer covered in a wet cloth over which air is passing.

This is relevant because it indicates the temperature that human skin can reach with any amount of sweat and wind. It is normally much lower than air temperature because of evaporative cooling effects; but, as humidity increases, WBT and air temperature get closer and closer; at 100% humidity, there is no more evaporation, so WBT becomes equal to air temperature.

The problems for human activity start at a WBT of 32C (90F), and a WBT of 35C (95F) means that even healthy humans with access to unlimited water will die of heat stroke in the shade after a few hours.

Argentina gets easily 30+ in the summer, 40+ is not unusual

Co-worker from Mumbai (yeah, here-say, I know) mentioned temperature up to 50C in the summer.

You cannot say what is responsible (if that’s possible at all) but you can say whether climate changes makes events more (or less) probable than they used to be. Such statements are usually based on simulations (ensembles) where the number of occurrences of particular events is counted. An example that‘s easy to understand is probability of precipitation from the weather forecast: if it says that the probability of rain is 72% at a particular place, then it means that rain was observed in 72% of the simulations (which are run with slightly different parameters to account for uncertainty in starting conditions). This is a simplified description but maybe it helps?

Agree. This is the third or fourth front page HN discussion about the recent couple days of heat in the Pacific Northwest, and all the discussions have been full of hot takes about climate change that unscientifically try to establish a cause without any statistical analysis or evidence.

Cliff Mass, Professor of Atmospheric Science and chief scientist of the Northwest Modeling Consortium mentioned in his recent blog posts that the heat wave was a perfect storm of factors like compression from sinking air coming off the West slopes of the Cascades. He also specifically noted (https://cliffmass.blogspot.com/2021/06/incredible-temperatur...):

> Is global warming contributing to this heatwave? The answer is certainly yes. Would we have had a record heatwave without global warming. The answer is yes as well.

While you are right in principle, right now Lytton is not just experiencing record temperatures, it's experiencing temperatures 5 C higher than anything encountered in the last 100-150 years (highest peak known before was 44.4C in 1941, 29 June 2021 was 49.6C):

https://en.wikipedia.org/wiki/List_of_extreme_temperatures_i...

Edit: corrected values to use the previous record for Lytton instead of the previous record for all of Canada.

So the mechanism is normal but there is just more energy being pumped into the system lately? That sounds crazy to me given the latitude but the geography explanation makes sense. The article said it's like a giant Death Valley.

My understanding is the hot air is high pressure, meaning no cold air can get in, and the mountains block movement of the system as a whole. This implies to me that the hotter it gets the more 'sticky' it might get in staying around for longer. Not sure if that's true but thunderstorms in dry heat are never great, they're a regular source of fires.

Sometimes yes, you are right, but this depend on the area.

I remember a study from the north of Spain concluding that only around 11% of the wildfires with known cause were by lightning. Most people would guess a much higher percentage if asked. In 2020, some places here experienced a 94% less wildfires than in previous years also. The only variable changing was humans. Everybody at home by covid19 = no wildfires.

To fellow Canadians with better direct experience here, are this hot waves being coupled with heavy (or dry) storms?