9 ms·

Even more unusual are the grass fires so close to London. Seeing people's homes destroyed is so tragic, particularly as I bet they would never have thought thi

Even more unusual are the grass fires so close to London. Seeing people's homes destroyed is so tragic, particularly as I bet they would never have thought this would be an issue here in the UK. Sky News have some astounding[0] footage[1]: [0]: https://www.youtube.com/watch?v=7NP7GF8xS5g https://www.youtube.com/watch?v=7NP7GF8xS5g [1]: https://www.youtube.com/watch?v=TjBV4R18ICY https://www.youtube.com/watch?v=TjBV4R18ICY ...and before the rest of you jump in saying this is regular in your country, please note that it is NOT regular here in the UK. Today, the UK has seen the highest temperature in ITS recorded history.

russfink 4y ago
But a lawn fire is not directly temperature related, is it? I suspect the grass has dried from lack of rain, such that some small spark that would ordinarily have fizzled has taken hold.
- secretsatan 4y ago
  It’s not like it would dry out quicker
- maigret 4y ago
  The lack of rain comes from the same climate emergency though, this has been confirmed scientifically as well.
  - salt-thrower 4y ago
    Not sure why you’re being downvoted. Weather patterns like droughts are exacerbated by climate change. Heat waves are known to make it easier for fires to catch and spread. Heat waves are more common now due to climate change. Thus climate change makes fires more likely/common. It’s pretty straightforward.
    - maigret 4y ago
      Yeah the jet stream is clearly slowing down because the temperature difference with the arctic is lower than before. But to be honest I don’t care much about my karma here. Thanks for the nice answer in any case
      - WalterBright 4y ago
        Please don't care about karma, as catering to it will make your posts less interesting.
    - feet 4y ago
      They're likely getting down voted because climate change deniers want to ignore the evidence that's beginning to scream at us
      - maigret 4y ago
        That’s a good point though. Many tell lobbies are at work, but I think many people can’t take such a harsh change, and I can understand that. We have to focus on changing step by step. The level at which renewables are taking over in many countries is giving me hope.
- danans 4y ago
  > But a lawn fire is not directly temperature related, is it? The rate of evaporation is directly related to the temperature. Even ignoring additional factors affecting evaporation like wind and topographic variance in dryness, the vapor pressure of water (the biggest contributor to evaporation rate) at 40C is an order of magnitude higher than it is at 20C: https://en.wikipedia.org/wiki/Evaporation#/media/File:Water_vapor_pressure_graph.svg https://en.wikipedia.org/wiki/Evaporation#/media/File:Water_... Sufficient subsequent days of high heat and low humidity will dry out a lawn very quickly, as grass is a plant that is not adapted to retain moisture very well. With hot/dry enough conditions for a sufficient period of time and a bit of kinetic energy in the form of wind, grass that isn't watered quickly becomes flammable, which is why it is usually where large fires first take hold.
- quarterdime 4y ago
  As a former wildland fire fighter, I can assure you that temperature (and wind and relative humidity) have a HUGE effect on fire behavior. Furthermore temperature and relative humidity (not so much wind) have a huge impact on ignition. My training emphasized this quite heavily, but I thought the effect was exaggerated until I experienced it first hand. In the Western US, construction, mining, forestry, etc. industries are well aware of the fire risk from routine work (construction equipment, off road vehicle traffic, chain saw work, etc.). In "red flag" conditions, there are fire watch policies. For example in forestry work, my crew would have to cease chain saw work late in the morning and stand a fire watch for 30 minutes before leaving the work site. So as I watch the news about these fires, my first thought is ignitions: routine activities (parking a vehicle on grass, driving construction equipment, discarding a cigarette) that would be unlikely to cause a fire in normal (backward looking) UK weather conditions. My next thought is that once a fire has started, it is likely to burn hot and fast. Hotter and faster than I suspect fire fighters in London are accustomed to. As an aside, I have been trying to figure out a good source for weather data. I see plenty of sources for temperature, but I am curious about the wind speeds and relative humidity. From the photos I am seeing, it looks like wind speeds are over 10 mph.
  - more_corn 4y ago
    ^ this is why we come to hacker news. Deep contextual comments from knowledgeable professionals. Thank you.
    - russfink 4y ago
      Agreed!
  - aeroman 4y ago
    You could try the Met Office website. This is a station in North West London https://www.metoffice.gov.uk/weather/observations/gcpvj0v07 https://www.metoffice.gov.uk/weather/observations/gcpvj0v07 Humidity was about 15-20% during the afternoon, winds 13 gusting 26mph.
    - 4y ago
- retard111 4y ago
- gdubs 4y ago
  If one pours gasoline all over the floor, yes, a match needs to be lit. But the gasoline all over the floor raises the risk of a disaster.
- Terretta 4y ago
  The ‘lawn fire’ that burned a village today started in a compost heap. Heat was categorically a factor. Together with the heat the compost pile spontaneously ignited. They went to get a hose to douse the smolder, but by the time they got back wind blew embers into dry grass, and woosh. A rare combination of events can cause a compost pile to catch fire. These all must be met before the occasion arises. - The first is dry, unattended material with pockets of debris mixed throughout that aren’t uniform. - Next, the pile must be large and insulated with limited airflow. - And, finally, improper moisture distribution throughout the pile. Key to preventing any issues is proper maintenance of your organic matter to prevent hot compost bins or piles. https://www.gardeningknowhow.com/composting/basics/overheated-compost-piles.htm https://www.gardeningknowhow.com/composting/basics/overheate...
nigerian1981 4y ago
While the right wing media in the UK ignored the climate crisis in their coverage and instead focused on the “positive” side with front pages full of children eating ice cream and people at the beach.
- nicky0 4y ago
  Weather is not climate though.
  - eurasiantiger 4y ago
    It really isn’t. People commonly think that the climate warming by a degree means that the weather warms up by a degree. However, there’s a good 100 miles of air above us, and that mass of air warming by a degree means that it can now retain a LOT more humidity before it starts precipitating as rain. This means coastal areas get drier and hotter, while mountaineous areas get much more rainfall (and more of it as water instead of snow), as well as flooding, mudslides, etc.
  - sangnoir 4y ago
    Yes, but do you think many parts of the world setting new heat records year after year is just weather, or climate-related? The point is moot,because the right wing channels are downplaying[1] the current extreme weather like it's no big deal - not just climate-change 1. https://twitter.com/MrMatthewTodd/status/1548353724086530049 https://twitter.com/MrMatthewTodd/status/1548353724086530049
ralferoo 4y ago
I saw the second video yesterday, but I found it interesting when watching it, because I also was looking at Google Maps to see where it was. https://youtu.be/TjBV4R18ICY?t=255 https://youtu.be/TjBV4R18ICY?t=255 (4m15 on your [1]) shows a lot of destroyed buildings and we're left to imagine that these are houses as it later cuts to images of houses and fire engines. But actually, if you look on Google Maps, you can see that it's actually a fireworks factory, a fairly important detail that was missed out. You can see it yourself at: https://www.google.com/maps/@51.4680241,0.2185786,453m/data=!3m1!1e3 https://www.google.com/maps/@51.4680241,0.2185786,453m/data=... the same layout of buildings and the label "Wells Fireworks Factory" in the centre of it.
- 12ian34 4y ago
  I found it interesting when reading your post, because I was also looking at Google to learn more about the factory. You can see it yourself[0] the fireworks factory was closed and abandoned in the 70s. A fairly important detail that was missed out! Not sure what the motive behind your message was, but peoples' homes were indeed destroyed in these fires[1]! [0]: https://www.remotelondon.com/wells-fireworks-factory-dartford-marshes/ https://www.remotelondon.com/wells-fireworks-factory-dartfor... [1]: https://www.itv.com/news/london/2022-07-19/major-incident-declared-across-london-as-heatwave-triggers-multiple-fires https://www.itv.com/news/london/2022-07-19/major-incident-de...
  - ralferoo 4y ago
    Oh good find. I know nothing about the history of the fireworks factory, but assumed it was still in use if it's labelled on Google Maps. It seemed likely that with such a use, this area would in fact be at higher risk than the surrounding grassland, and I wondered if maybe that was the source of the initial fire. And yes, I had seen later footage of actual houses destroyed, and it wasn't my intention to take away from that, I just saw something that seemed interesting and overlooked. But, if the site has been abandoned for half a century, that is unlikely, so my speculation is moot.

russfink 4y ago

But a lawn fire is not directly temperature related, is it? I suspect the grass has dried from lack of rain, such that some small spark that would ordinarily have fizzled has taken hold.

secretsatan 4y ago
It’s not like it would dry out quicker
maigret 4y ago
The lack of rain comes from the same climate emergency though, this has been confirmed scientifically as well.
- salt-thrower 4y ago
  Not sure why you’re being downvoted. Weather patterns like droughts are exacerbated by climate change. Heat waves are known to make it easier for fires to catch and spread. Heat waves are more common now due to climate change. Thus climate change makes fires more likely/common. It’s pretty straightforward.
  - maigret 4y ago
    Yeah the jet stream is clearly slowing down because the temperature difference with the arctic is lower than before. But to be honest I don’t care much about my karma here. Thanks for the nice answer in any case
    - WalterBright 4y ago
      Please don't care about karma, as catering to it will make your posts less interesting.
  - feet 4y ago
    They're likely getting down voted because climate change deniers want to ignore the evidence that's beginning to scream at us
    - maigret 4y ago
      That’s a good point though. Many tell lobbies are at work, but I think many people can’t take such a harsh change, and I can understand that. We have to focus on changing step by step. The level at which renewables are taking over in many countries is giving me hope.
danans 4y ago
> But a lawn fire is not directly temperature related, is it? The rate of evaporation is directly related to the temperature. Even ignoring additional factors affecting evaporation like wind and topographic variance in dryness, the vapor pressure of water (the biggest contributor to evaporation rate) at 40C is an order of magnitude higher than it is at 20C: https://en.wikipedia.org/wiki/Evaporation#/media/File:Water_vapor_pressure_graph.svg https://en.wikipedia.org/wiki/Evaporation#/media/File:Water_... Sufficient subsequent days of high heat and low humidity will dry out a lawn very quickly, as grass is a plant that is not adapted to retain moisture very well. With hot/dry enough conditions for a sufficient period of time and a bit of kinetic energy in the form of wind, grass that isn't watered quickly becomes flammable, which is why it is usually where large fires first take hold.
quarterdime 4y ago
As a former wildland fire fighter, I can assure you that temperature (and wind and relative humidity) have a HUGE effect on fire behavior. Furthermore temperature and relative humidity (not so much wind) have a huge impact on ignition. My training emphasized this quite heavily, but I thought the effect was exaggerated until I experienced it first hand. In the Western US, construction, mining, forestry, etc. industries are well aware of the fire risk from routine work (construction equipment, off road vehicle traffic, chain saw work, etc.). In "red flag" conditions, there are fire watch policies. For example in forestry work, my crew would have to cease chain saw work late in the morning and stand a fire watch for 30 minutes before leaving the work site. So as I watch the news about these fires, my first thought is ignitions: routine activities (parking a vehicle on grass, driving construction equipment, discarding a cigarette) that would be unlikely to cause a fire in normal (backward looking) UK weather conditions. My next thought is that once a fire has started, it is likely to burn hot and fast. Hotter and faster than I suspect fire fighters in London are accustomed to. As an aside, I have been trying to figure out a good source for weather data. I see plenty of sources for temperature, but I am curious about the wind speeds and relative humidity. From the photos I am seeing, it looks like wind speeds are over 10 mph.
- more_corn 4y ago
  ^ this is why we come to hacker news. Deep contextual comments from knowledgeable professionals. Thank you.
  - russfink 4y ago
    Agreed!
- aeroman 4y ago
  You could try the Met Office website. This is a station in North West London https://www.metoffice.gov.uk/weather/observations/gcpvj0v07 https://www.metoffice.gov.uk/weather/observations/gcpvj0v07 Humidity was about 15-20% during the afternoon, winds 13 gusting 26mph.
  - 4y ago
retard111 4y ago
gdubs 4y ago
If one pours gasoline all over the floor, yes, a match needs to be lit. But the gasoline all over the floor raises the risk of a disaster.
Terretta 4y ago
The ‘lawn fire’ that burned a village today started in a compost heap. Heat was categorically a factor. Together with the heat the compost pile spontaneously ignited. They went to get a hose to douse the smolder, but by the time they got back wind blew embers into dry grass, and woosh. A rare combination of events can cause a compost pile to catch fire. These all must be met before the occasion arises. - The first is dry, unattended material with pockets of debris mixed throughout that aren’t uniform. - Next, the pile must be large and insulated with limited airflow. - And, finally, improper moisture distribution throughout the pile. Key to preventing any issues is proper maintenance of your organic matter to prevent hot compost bins or piles. https://www.gardeningknowhow.com/composting/basics/overheated-compost-piles.htm https://www.gardeningknowhow.com/composting/basics/overheate...

nigerian1981 4y ago

While the right wing media in the UK ignored the climate crisis in their coverage and instead focused on the “positive” side with front pages full of children eating ice cream and people at the beach.

nicky0 4y ago
Weather is not climate though.
- eurasiantiger 4y ago
  It really isn’t. People commonly think that the climate warming by a degree means that the weather warms up by a degree. However, there’s a good 100 miles of air above us, and that mass of air warming by a degree means that it can now retain a LOT more humidity before it starts precipitating as rain. This means coastal areas get drier and hotter, while mountaineous areas get much more rainfall (and more of it as water instead of snow), as well as flooding, mudslides, etc.
- sangnoir 4y ago
  Yes, but do you think many parts of the world setting new heat records year after year is just weather, or climate-related? The point is moot,because the right wing channels are downplaying[1] the current extreme weather like it's no big deal - not just climate-change 1. https://twitter.com/MrMatthewTodd/status/1548353724086530049 https://twitter.com/MrMatthewTodd/status/1548353724086530049

ralferoo 4y ago

I saw the second video yesterday, but I found it interesting when watching it, because I also was looking at Google Maps to see where it was. https://youtu.be/TjBV4R18ICY?t=255 https://youtu.be/TjBV4R18ICY?t=255 (4m15 on your [1]) shows a lot of destroyed buildings and we're left to imagine that these are houses as it later cuts to images of houses and fire engines. But actually, if you look on Google Maps, you can see that it's actually a fireworks factory, a fairly important detail that was missed out. You can see it yourself at: https://www.google.com/maps/@51.4680241,0.2185786,453m/data=!3m1!1e3 https://www.google.com/maps/@51.4680241,0.2185786,453m/data=... the same layout of buildings and the label "Wells Fireworks Factory" in the centre of it.

12ian34 4y ago
I found it interesting when reading your post, because I was also looking at Google to learn more about the factory. You can see it yourself[0] the fireworks factory was closed and abandoned in the 70s. A fairly important detail that was missed out! Not sure what the motive behind your message was, but peoples' homes were indeed destroyed in these fires[1]! [0]: https://www.remotelondon.com/wells-fireworks-factory-dartford-marshes/ https://www.remotelondon.com/wells-fireworks-factory-dartfor... [1]: https://www.itv.com/news/london/2022-07-19/major-incident-declared-across-london-as-heatwave-triggers-multiple-fires https://www.itv.com/news/london/2022-07-19/major-incident-de...
- ralferoo 4y ago
  Oh good find. I know nothing about the history of the fireworks factory, but assumed it was still in use if it's labelled on Google Maps. It seemed likely that with such a use, this area would in fact be at higher risk than the surrounding grassland, and I wondered if maybe that was the source of the initial fire. And yes, I had seen later footage of actual houses destroyed, and it wasn't my intention to take away from that, I just saw something that seemed interesting and overlooked. But, if the site has been abandoned for half a century, that is unlikely, so my speculation is moot.