Flash flooding

What is a flash flood?

Flash flooding happens when an exceptional amount of rain falls in a very short time. This type of flood happens very quickly and is particularly dangerous and extremely destructive, so being prepared could save lives and property.

During the summer months the risk of flash flooding from torrential downpours and thunderstorms increases. The geography of Calderdale makes us more susceptible to these kinds of weather events which can be very isolated, hitting one community whilst leaving neighbouring localities untouched.


Climate change

Because of climate change, we are experiencing heavier and more frequent downpours that put extra stress on all drainage systems. This increases the risk of flash flooding because drainage systems and small rivers can be overwhelmed in all areas, potentially affecting properties previously thought safe from flooding, not just those in the valley bottoms.


Is there anything else I can do?

The most important thing you can do is take the risk of flash flooding seriously.

Flash flooding can happen very quickly, and there is often no time to issue flood warnings beforehand. However, the free Floodline service will give you advance warning of flooding from rivers and the sea. You can sign up for free flood warnings here or by phoning Floodline on 0345 988 1188.

The best ways to protect yourself from these kind of events are to sign up to the Met Office weather warning service and familiarise yourself with your local area. Are there streams, culverts, roads and drains which are vulnerable to downpours? If you are new to an area, talk to your neighbours or local flood group and find out if they’ve experienced flash flooding before.

If you live in an area at specifically at risk of flash flooding, consider writing a personal flood plan and investing in property level protection. You could also install sustainable drainage systems to slow the flow of rainwater into drains, gutters and rivers.


Be aware and know the signs

It is important to know what signs to look for in your location so that you can ACT FAST

Watch out for the following, and treat them as signs that a flash flood could be on its way:

  • heavy rain or severe weather reports
  • rising water levels with churning dark water
  • a build-up of debris in rivers or streams.


What to do if a flash flood happens

Take these quick and simple measures to minimise the impact on you and your property:

  • Listen to local radio and TV for warnings and advice.
  • Move furniture and valuables upstairs if you can.
  • Roll up carpets and rugs if possible and move them out of harm’s way.
  • Put plugs in downstairs sinks and baths and weigh them down.
  • Bring outdoor pets indoors and upstairs where possible.
  • Prepare a pack with essential items i.e. prescriptions, important documents, baby items etc.
  • Turn off the gas and electricity supply.
  • Evacuate if asked to do so by the emergency services.
  • Never walk or drive through floodwater, as there may be hidden dangers such as open manholes.
  • Keep yourself safe; dial 999 if your life or health is at risk.