Dartmoor Society member, Mike Sampson, has been monitoring the weather on Dartmoor for over 50 years. Formerly with the Environment Agency and now in his retirement he is increasingly observing and monitoring bird life, especially in the pools created by the peat resortation works. Each year, he kindly sends us his round up of the previous year’s weather.
DARTMOOR RAINFALL IN 2023
Weather on Dartmoor during 2023 was of exceptional interest as it was the second
wettest year ever recorded and indeed some places recorded the most since records
began including Cut Hill and Plym Head. Yet in complete contrast it was so dry in
May and early June that most water pools dried up leaving only those created by the
mire restoration project remaining. This was most unusual so early in the season but
was limited to the moorland surface as the rivers and streams although low were
nowhere near record low levels as measured by the gauging stations.
January saw up to 12inches of snow lying for a while which contributed to a wet start for the year, Cut Hill which is very representative of the high moor recorded 444 millimeters (17.48 inches) February was hardly ‘fill dyke’ as just 84mm (3.3ins) fell but then came March when a huge 508mm (20.0ins) was measured and at nearby Black Hill even more with 560mm(22 ins). April recorded 141mm (5.5ins) for Cut Hill then another 95mm (7.6ins) up to mid May. This was followed not by just a dry spell but an exceptional period with blazing sunshine and dry strong winds with so much evaporation that simply dried the moorland surface up. It was hard to find any natural water pools and even the Mire
restoration pools on Hangingstone and Black Hill were much reduced. Then this was followed by a huge amount of rain for July with 434mm (17.1ins). This would have been quite a disaster for wildlife and birds. August continued the wet theme with 205mm (8.07 ins) and almost the same 207mm (8.1ins) in September. October had slightly more rain with 220mm (8.66ins). So with so much rain the last thing that was needed was to have a really wet spell- but that happened. November recorded 408mm (16.1ins) at Cut Hill and 463mm (18.2ins) To finish the year off 604 mm (23.8ins) fell at Black Hill and 510mm (20.1ins @ Cut Hill- It was quite a challenge to get the true amounts of rain on the North moor in what was a short weather window on the first of January before the onset of really wet and windy conditions set in.
Total rain at Cut Hill was 3304mm (130.08ins) the most in 47 years of record and average of 2589mm (101.92ins) Black Hill recorded 3608mm (142.05ins) in this case 2020 was slightly wetter. At Varracombe rainfall was 2998mm (118.03ins) and Sandyhole 3234mm (127.32ins). Lastly for the north moor Wilsworthy recorded 2023mm (92.0ins) second to 2020 with 46 years of records.
On the south moor conditions were much the same for the year with 3312mm(130.4ins) measured at Green Hill At this location both 2000 and 2220 had been very slightly wetter by 100mm (4.0 inches) ! Plym Head recorded 3228mm (127.1 ins) the most there over a 36 year period. Langcombe Head (nearYealm Head) recorded 3050mm (120.1ins) and this was slightly less that in 2020. Tor Royal near South Hessary Tor measured 3171mm (124.8ins) which again was just under the 2020 record. Representing the central moor East Bovey Head recorded 2598mm
(102.3ins) the most there in 16 years and Corndon Hill 2418mm (95.2ins) second wettest year over 21 years.
Despite such a wet year although there were lots of high river flows recorded at the gauging stations at Bellever and Dunnabridge none of the peaks reached the record levels measured in the past as there had not been any large falls of rain in a short time.