The August Heatwave(s) in Cornwall

For the previous article in this series (which is becoming overly lengthy!) please see:

Drought for Cornwall later in 2022?

As the weeks have passed the answer to that question seems increasingly likely to be “Yes”. Hence we’ll begin August 2022 with the current water levels of Cornish reservoirs provided by the South West Lakes Trust:

South West Water also provide graphs for the largest two:

As you can see the water levels in both Colliford and Stithians reservoirs are already below their lowest levels last year. Colliford is also well below its level at the beginning of August 1995, a particularly dry year for Cornwall and other parts of the United Kingdom.

For reference, here’s how our local Crowdy Reservoir looked on July 30th 2022 when almost exactly half full:

Yesterday the Met Office issued a Level 2 heat-health watch across southern England for the coming week:

Here too is this morning’s Met Office weather forecast for the Camelford area:

As well as the high temperatures forecast by the end of next week, here is the Met Office weather model’s forecast of total rainfall over the next seven days:

A negligible amount across Cornwall, and the medium range forecasts don’t look any better. Although it’s far from certain this is how things will ultimately pan out, the GFS forecast is for temperatures to reach 30 °C here on Monday 15th:

[Edit – August 8th]

Here is this morning’s Met Office weather forecast for the Davidstow vicinity:

and here is their map of heat wave temperature thresholds:

Hence it comes as no surprise that this morning the heat health alert for Cornwall has been upgraded to level 3 – “Heatwave Action”:

It may come as some consolation that a sprinkling of rain is currently forecast for the coming weekend. This map shows the total predicted rainfall until 1 AM on Monday morning:

It looks as though Cornwall needs some more moisture!

“True colour” image of Cornwall on August 8th from the MODIS instrument on the Terra satellite

[Edit – August 9th]

Things have already started warming up here in Davidstow. The thermometer in my office currently reads 23.7 °C. Here’s the Met Office’s weather forecast for the rest of this week:

As you can see, they have now issued an amber warning for a heatwave from Thursday to Sunday:


The Met Office weather model is suggesting the distinct possibility of us reaching at least 30 °C on Saturday afternoon :


By way of a second opinion the GFS model currently predicts 35 °C !

[Edit – August 10th]

South West Water have released last week’s water level data for Colliford and Stithians reservoirs:

The water level at Colliford reduced by 3.3% of its total net capacity last week. Stithians fell by 4.3%.

Note that I have recently established that Stithians is not in fact the second largest of South West Water’s Cornish reservoirs in terms of “gross” capacity:

Hence I am forced to wonder how Stannon and Park reservoirs compare to Stithians in terms of “net” capacity. However discovering the current water level and abstraction rate of Stannon and Park is proving to be a non trivial task!

[Edit – August 12th]

The South West Lakes Trust has just updated its table of reservoir water levels to the week ending August 7th:

Our local Crowdy Reservoir is down to 48% of total capacity, another decline of 4% (to zero decimal places) in one week.

As far as I can tell there hasn’t been an official announcement yet, but according to documents “leaked ” to the Guardian:

A drought has been declared across wide swathes of England after a meeting of experts.

The prolonged dry conditions, with some areas of the country not receiving significant rainfall all summer, have caused the National Drought Group to declare an official drought.

The Environment Agency has moved into drought in eight of its 14 areas: Devon and Cornwall, Solent and South Downs, Kent and south London, Herts and north London, East Anglia, Thames, Lincolnshire and Northamptonshire, and the east Midlands…

Water minister Steve Double said: “We are currently experiencing a second heatwave after what was the driest July on record for parts of the country. Action is already being taken by the government and other partners including the Environment Agency to manage the impacts. All water companies have reassured us that essential supplies are still safe, and we have made it clear it is their duty to maintain those supplies.

P.S. Here is the official press release, which points out that:

This change in status to drought is a change in categorisation, indicating the impact prolonged dry weather is having on water resources and the environment. It does not automatically trigger actions itself, but moving to drought status means that the Environment Agency and water companies will step up their actions to manage the impacts and press ahead with implementing the stages of their pre-agreed drought plans. These plans follow local factors including reservoir levels, demand and forecasts, and lead to precautionary actions such as Temporary Use Bans. The last drought in England was 2018.

[Edit – August 15th]

Following last Friday’s meeting of the National Drought Group South West Water announced a temporary use ban this morning:

From 00:01am on 23 August 2022, customers who get their water from us in Cornwall and a small part of Devon will not be allowed to use a hosepipe.

It’s the first time in 26 years but we’ve been left with no other choice. We need to have a hosepipe ban now to protect our precious water.

We’ve done our best to avoid this ban. We’ve increased the amount of water we can store – doubling it since the last drought in 1976. We’ve opened reservoirs, installed a new borehole, and improved the way we can move water across the region to help keep everyone’s taps running. At the same time, we’ve reduced the amount of water lost through our own pipes. In the last two years we’ve doubled the amount of leak detection staff and now fix about 2,000 leaks a month. 30% of leaks happen on customer supply pipes, we’ve offered to fix these leaks for free. But all of this hasn’t been enough.

The “small print” for the “hosepipe ban” can be downloaded at this link.

Perhaps there is causal link between this morning’s announcement of a hosepipe ban and the current thunder, lightning and rain in the Davidstow vicinity?

[Edit – August 17th]

South West Water have released last week’s water level data for Colliford and Stithians reservoirs:

The water level at Colliford reduced by 2.8% of its total net capacity last week. Stithians fell by 4.9%.

[Edit – August 18th]

The South West Lakes Trust has just updated its table of reservoir water levels to the week ending August 14th:

Our local Crowdy Reservoir is down to 43% of total capacity, a decline of 5% (to zero decimal places) in one week.

[Edit – August 24th]

South West Water’s “hosepipe ban” has started, and they have released last week’s water level data for Colliford and Stithians reservoirs:

The water level at Colliford reduced by 2.8% of its total net capacity last week. Stithians fell by 4.2%.

Here’s the last four weeks record from the automated rainfall gauge 49104 at Colliford Lake:

[Edit – August 25th]

The South West Lakes Trust has updated its table of reservoir water levels to the week ending August 21st:

Our local Crowdy Reservoir is down to 42% of total capacity, a decline of a mere 1% in one week. The same cannot be said for Upper Tamar Reservoir north of here, which has lost 4% in a week and is down to 27% of total net capacity.

The next article in our “Drought 2022” series can be viewed at:

The 2022 Drought in Cornwall

15 Replies to “The August Heatwave(s) in Cornwall”

  1. I stumbled upon this tweet from Chris Stark, Chief Executive of the UK’s Climate Change Committee, earlier this morning

    This is the August river flow forecast for Cornwall:

    Low everywhere.

  2. Here’s this morning’s Met Office weather forecast for the Camelford area:

    The maximum temperature for the current heatwave is now up to 30 °C on Thursday, with some much needed rain forecast next Tuesday.

  3. Here’s this afternoon’s Met Office weather forecast for the Camelford area:

    “Cloudy changing to heavy showers in the afternoon” is now the summary of next Monday’s weather.

    According to the Met Office’s “unofficial” Weather Observations Website temperatures have reached 33 °C in Poundstock, slightly inland from Bude:

  4. Here’s this morning’s Met Office weather forecast for the Camelford area:

    The forecast for Tuesday now states “Light showers changing to thunder by lunchtime.”

    That will be nice, if it verifies!

  5. Here is this afternoon’s Met Office weather forecast for the Camelford area:

    The thunderstorms in this morning’s forecast seem to have vanished, but there are still “light showers in the afternoon” on Monday, and somewhat heavier showers on Tuesday.

    The Met Office’s “unofficial” WOW site shows temperatures topping 30 °C at several locations in North Cornwall:

    The temperature indoors in my Davidstow home/office has reached 27 °C.

  6. Yorkshire Water have announced a hosepipe ban starting on August 26th:

    You’ve heard of dry January – well, in Yorkshire we’ve had dry March, April, May, June and July, with 34% less rain than the long term average.

    The forecast’s looking similar for August. And while our teams are out 24/7 fixing leaks and looking after your water, we’re asking for your help to use a bit less too.

    To ensure we’re able to apply for drought permits this winter, we are putting a hosepipe ban in place from 26 August 2022, which would mean the following activities are prohibited:

    • Watering a garden using a hosepipe
    • Cleaning a private motor-vehicle using a hosepipe
    • Watering plants on domestic or other non-commercial premises using a hosepipe
    • Cleaning a private leisure boat using a hosepipe
    • Filling or maintaining a domestic swimming or paddling pool
    • Drawing water, using a hosepipe, for domestic recreational use
    • Filling or maintaining a domestic pond using a hosepipe
    • Filling or maintaining an ornamental fountain
    • Cleaning walls, or windows, of domestic premises using a hosepipe
    • Cleaning paths or patios using a hosepipe
    • Cleaning other artificial outdoor surfaces using a hosepipe

    Customers can still carry out these activities if they use water from a bucket or watering can; or use water that is not sourced from the mains such as grey water, rainwater from a water butt through a hosepipe, or private boreholes for example.

  7. Here’s this morning’s Met Office weather forecast for the Camelford area:

    The Met Office has also issued a yellow warning for thunderstorms on Monday:

    Let’s hope they’re right about that!

  8. I am the bearer of exciting news this morning. There are some clouds in the sky!

    However the forecast is for them to disappear soon, resulting in the hottest day of the current heatwave for Davidstow:

  9. Here’s some more exciting news! According to the rain radar Bodmin Moor received a light sprinkling earlier this morning:

    However the current clouds don’t look as though they’re bearing any rain:

    What’s more the Met Office forecast for the Camelford area predicts no rain here until the small hours of tomorrow morning, preceded by the mist so familiar in this part of the world:

    The yellow thunderstorm warning for South West England has been extended to Wednesday:

  10. The Met Office has updated its thunderstorm warning for North Cornwall to “amber”:

    Fast flowing or deep floodwater is likely, causing danger to life

    Now we’re in the midst of another round of thunder, lightning and rain:

  11. Some less exciting, if not unexpected, news. We had a bit of rain in Cornwall yesterday, after a long period of dry weather.

    Today we have lots of sewage pollution as well:

    and some more rain on the way:

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