Impact evaluation of snow storm in Madrid, Spain

In this post

We developed this impact assessment to evaluate the damage to road infrastructure across the Community of Madrid after Storm Filomena in January 2021 and to monitor recovery in the weeks that followed.

Beyond everyday mobility, road accessibility was critical. The transport networks enabled the delivery of essential goods — including food and COVID-19 vaccines — at a time when logistics could not afford disruption.

For the evaluation we focused on the following questions:

Where did the greatest impact actually occur?
Which municipalities were most affected?
Who responded the fastest?
How long did full recovery take?

Snow Extent Mapping

We processed satellite imagery from before, during, and after the storm to map snow extent and track its evolution between 6 January and 5 February 2021.

snow_evolution

Storm evolution between January 6th and February 5th 2021

Road Mapping

We integrated official road infrastructure data from open sources to analyse exposure and disruption at municipal level.

madrid_map

Impact quantification & evolution

We measured snow impact through change detection against a pre-storm baseline. Snow-covered roads exhibit a different spectral response than exposed pavement, allowing us to identify:

– Which roads were affected
snow_impact

By analysing multiple dates, we also captured the progression of snow removal efforts across the region.

We generated operational indicators, including:

Quick response rate — the reduction in snow-covered road surface between the first two recorded dates.
Cleaning time — the number of days required to clear 90% of affected roads.

These indicators provided an objective measure of response efficiency across municipalities.