6 hours ago, Ray Proudfoot said:

Grass doesn’t spontaneously combust.

In parts of Texas, this time of year is called 'fire season'  due to high temps, low humidity, and strong south winds.  Some reported causes of fires that I remember are lightning, careless motorists with cigarettes and sparks from passing trains.  I'm sure all those exist in France so although some may be arson, Im sure most is not intentional.

 

The only correlation between hot air temps and fires is "stupid people"!  Baby gender reveal parties with color (blue or pink) explosions, pouring half a container of charcoal lighter on the bar-b-que grill, mowing tall, dry grass with a power mower and causing a spark to ignite.  I see it all of the time on the news.  Hot temps and high winds today and various fires all over the place.

27 minutes ago, sightseer said:

In parts of Texas, this time of year is called 'fire season'  due to high temps, low humidity, and strong south winds.  Some reported causes of fires that I remember are lightning, careless motorists with cigarettes and sparks from passing trains.  I'm sure all those exist in France so although some may be arson, Im sure most is not intentional.

We’ll have to agree to disagree. Four years ago the moors to the east of Manchester at 54°N were ablaze for many miles and very difficult for fire engines to reach. Those were started deliberately or accidentally by idiots. You don’t get fires starting up there by sparks from trains or lightning. It’s a very isolated area.

Anyway, good news. The temperature has started to drop and is now 33.8°C (down from 38.7°C) with the wind veering to the west. 👍

We get dry lightning here Ray.  Lightning without precipitation.  Usually accompanied by high winds.

High winds can cause trees to topple onto power lines and cause forest fires.  PG&E in California has been blamed for some of the biggest fires in the state's history.

https://nypost.com/2022/01/05/pge-blamed-for-massive-northern-california-wildfire/

Dry brush is also a contributing fire.  Brush and downed trees in drought areas cause forest fires to spread rapidly and make it difficult to bring them under control.

Noel

1 hour ago, charliearon said:

The only correlation between hot air temps and fires is "stupid people"!

 

Not always. Usually but not always. Spontaneous combustion is possible. 

 

Quote

As mentioned before, temperature affects the sparking of wildfires, because heat is one of the three pillars of the fire triangle. The sticks, trees and underbrush on the ground receive radiant heat from the sun, which heats and dries potential fuels. Warmer temperatures allow for fuels to ignite and burn faster, adding to the rate at which a wildfire spreads. For this reason, wildfires tend to rage in the afternoon, when temperatures are at their hottest.

 

https://science.howstuffworks.com/nature/natural-disasters/wildfire.htm#:~:text=The sticks%2C trees and underbrush,at which a wildfire spreads.

Quote

Spontaneous combustion or spontaneous ignition, as it is often called, is the occurrence of fire without the application of an external heat source. Due to chemical, biological, or physical processes, combustible materials self-heat to a temperature high enough for ignition to occur.

https://core.ac.uk/download/pdf/38890058.pdf

 

And of course in very hot conditions, when the fuel source is dried out, human carelessness is more likely to cause a fire. A dropped cigarette is less likely to start a blaze when dropped on moist undergrowth than when dropped on dried out fuel due to a heat wave. 

Edited July 19, 20223 yr by martin-w

1 hour ago, birdguy said:

We get dry lightning here Ray.  Lightning without precipitation.  Usually accompanied by high winds.

High winds can cause trees to topple onto power lines and cause forest fires.  PG&E in California has been blamed for some of the biggest fires in the state's history.

https://nypost.com/2022/01/05/pge-blamed-for-massive-northern-california-wildfire/

Dry brush is also a contributing fire.  Brush and downed trees in drought areas cause forest fires to spread rapidly and make it difficult to bring them under control.

Noel

I’m not disputing any of that Noel but Western Europe is very different to North America. We may never know what triggered those fires in France, Spain and Portugal but they are becoming increasingly frequent.

The temperature drop has stalled. Bugger. Stuck at 32.7°C. There is a cold front stretching NNE/SSW to the SW of me making slow progress and with not much rain on it. Just need it to move through before bedtime so I can get a better night’s sleep.

4 minutes ago, Ray Proudfoot said:

The temperature drop has stalled. Bugger. Stuck at 32.7°C. There is a cold front stretching NNE/SSW to the SW of me making slow progress and with not much rain on it. Just need it to move through before bedtime so I can get a better night’s sleep.

 

Yes, well our brief burst of rain and thunder has vanished. Only 20C outside and a slight breeze. But plenty of heat has been retained indoors. 

2 hours ago, Ray Proudfoot said:

And it’s 91°F in my lounge. 

😟

This morning in East Devon it was Borneo, this afternoon was Kenyan.

Phew.

I've noticed that the record temperature readings of 39C and 40C were taken at Gatwick and Heathrow airports, respectively.

Airports, like large cities, are some of the hottest areas due to all the concrete and asphalt which absorb lots of heat, not to mention the hot exhaust from all the aircraft engines.

Are these temperatures really representative of the actual temperature in other parts of the UK?

Dave

31 minutes ago, dave2013 said:

I've noticed that the record temperature readings of 39C and 40C were taken at Gatwick and Heathrow airports, respectively.

Airports, like large cities, are some of the hottest areas due to all the concrete and asphalt which absorb lots of heat, not to mention the hot exhaust from all the aircraft engines.

Are these temperatures really representative of the actual temperature in other parts of the UK?

Dave

Yes, they are breaking records all over the UK...  This is no different than when we have heat waves in areas of the Pacific Northwest where no one is used to it and the facilities aren't built for it.  It can be 100F here on the East Coast and they will still declare a heat warning which enacts certain provisions like cooling centers etc but life goes on.  100F in Seattle on the other hand could be crippling for the entire city and a heat emergency.  People aren't used to it and their homes and offices aren't built for it.  

Same heat, very different impacts.  

 

44 minutes ago, dave2013 said:

I've noticed that the record temperature readings of 39C and 40C were taken at Gatwick and Heathrow airports, respectively.

Airports, like large cities, are some of the hottest areas due to all the concrete and asphalt which absorb lots of heat, not to mention the hot exhaust from all the aircraft engines.

Are these temperatures really representative of the actual temperature in other parts of the UK?

Dave

 

It was also 39.1 in the village of Charlwood. I recall Coningsby too. Surrey 39 too.

It was the hottest night on record for the whole UK last night of course. 

And of course we've not had 40 at Heathrow before. 

 

 

Edited July 19, 20223 yr by martin-w

1 hour ago, martin-w said:

 

But plenty of heat has been retained indoors. 

This is just what I was just thinking of. If we had say 30 straight days of highs in the 30's and lows in the 20's (to an American that might sound cold), and even if no record highs were made, it would probably feel quite hellish, worse than this. Imagine a small apartment facing the sun with maybe only one window, only on one side, hard to get a draft going.

1 minute ago, Antipodeslonghaul said:

Imagine a small apartment facing the sun with maybe only one window, only on one side, hard to get a draft going.

 

My upstairs is in the roof, roof highly insulated, so you can image what a heat trap it is. Downstairs is different, old sash windows, single paned, no insulation. Granite walls though. 

47 minutes ago, dave2013 said:

I've noticed that the record temperature readings of 39C and 40C were taken at Gatwick and Heathrow airports, respectively.

Airports, like large cities, are some of the hottest areas due to all the concrete and asphalt which absorb lots of heat, not to mention the hot exhaust from all the aircraft engines.

Are these temperatures really representative of the actual temperature in other parts of the UK?

Dave

Dave, are you really suggesting professional meteorologists don't know the rules about placement of instruments. Really??

The highest temperature recorded so far is at Coningsby, Lincolnshire. About 100 miles north of London.

The cooler air is tantalisingly close...