lanky
  • lanky
  • Advanced Member Topic Starter
19 November 2019 17:18:06

The Met Office have published some of the data from the rain event from South Yorkshire and the North Midlands from 6th-7th November 2019


https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/weather/learn-about/uk-past-events/interesting/2019/2019_012_november_rain.pdf


The rainfall chart in the document for totals over the 2 days is below



Referring back to the Met Office daily rainfall data for 1 km grid squares


http://data.ceda.ac.uk/badc/ukmo-hadobs/data/insitu/MOHC/HadOBS/HadUK-Grid/v1.0.0.0/1km/rainfall


It is clear that this event was far from unprecedented and has been exceeded or equalled on probably 5 occasions in the last 46 years

The gif charts below show the rainfall distributions for these 5 occasions and the events of 1973 and 2 in 2007 clearly exceed the 2019 event



The factors which seem to have combined to render the current event more serious are

        The previous events were all in the summer when the ground is generally drier and evaporation more rapid
        The generally wet autumn this year
        A previous event in October 2019

These factors will have led to river levels already higher then average

However, with a return period of 10-20 years based on recent previous occurrences, an event such as those in 1973 or 2007 occurring during an already wet autumn could proved even more disastrous


Martin
Richmond, Surrey
DEW
  • DEW
  • Advanced Member
20 November 2019 17:20:09

Interesting. Thanks for heads-up


War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
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