Such thunderstorm cells can theoretically occur anywhere, and this is precisely why loss prevention is so challenging. But the local surroundings can also influence the risk of flash floods. Sparse vegetation, steep hills, and densely built-up spaces all contribute to accelerated surface water run-off. It takes a lot of planning and expense to build flood control infrastructure or to dig huge drainage culverts under roads. And given the fact that extreme weather events are typically very rare at any given location, such expense is often unwarranted. Municipal maps, on the other hand, showing the probabilities of heavy rainfall allow planners to identify where flooding, traffic disruption, blockages by debris and other threats are likely, and what drainage areas the local authorities need to protect. This information can help in drafting evacuation plans, and allows emergency personnel and residents to conduct suitable drills. The German Insurance Association (GDV) is currently working on a countrywide map of heavy rain zones, which they hope to have available by 2019. But households can also do their bit by ensuring that basement windows are well sealed, installing backwater valves, and refraining from storing valuable items in basements, for example. Flood insurance against conceivable losses should be a key component in any risk prevention plan, even far away from rivers, since heavy rain can happen in any region and affect everyone. As such events are localised and can happen anywhere, they are easily insurable. And premiums for this kind of enhanced natural hazard insurance tend not to be very high.