We have scored the climate risk of the 2.721 buildings in Alella using Cadastre data, satellite imagery and climate projections, and added it up by area, street and watercourse. The clearest change comes at night: from 42 to 80 tropical nights a year by 2050.
Level of the highest hazard in each 250 m area by 2050: flooding, heat, wildfire, wind or ground movement.
Position among the 8.217 municipalities: further right means more risk. These are figures for the municipality as a whole, the same for everyone; they may differ from those for the typical building. Compare with others →
It comes from matching each building with its neighbourhood, its street, the nearest watercourse and its surroundings.
These are 1.029 buildings right next to vegetation that can burn. Of these, 7 are blocks of flats with 206 homes, where evacuation is harder.
Proximity to woodland and to burnt areas (ESA WorldCover, EFFIS). It does not measure the state of the vegetation or any firebreaks.
In a typical building in Alella, nights when the temperature stays at or above 20 °C would rise from 42 a year (1991-2020) to about 80 by 2050. For this reason, 100 % of homes would be at a high or very high level.
Median of the buildings. Intermediate-to-high emissions scenario (SSP3-7.0).
Around homes with between 2 and 5 % tree cover, the surface in summer is 0,7 °C above the median for Alella; with more than 40 % tree cover, 1,8 °C below. 0 homes are in surroundings with almost no trees.
Ground surface temperature (Landsat), not air temperature. More trees usually go with less asphalt and lower density: this is a correlation, not a measure of the effect of planting trees.
Along Riera d'Alella (3,3 km within the municipality, dry most of the year) there is no official mapped flood zone, but there are 279 homes less than 50 m from the watercourse.
Having no official map does not mean it cannot overflow: watercourses that are dry most of the year are the ones that cause the most surprises in a storm.
Schools whose surroundings are at least 1 °C hotter than the municipal median in summer. They are the first candidates for shade and tree-lined playgrounds.
Ground surface temperature (Landsat) around the building closest to the OpenStreetMap point.
The 4.098 homes in Alella by the level of their building. Tap a hazard to see it on the map.
The same data for all 8.217 municipalities in Spain. Choose what to compare with: municipalities of a similar size, the province, the region or the whole of Spain.
Compared with the 893 municipalities with between 5.000 and 20.000 inhabitants. The bar shows where Alella stands: further right means more risk.
| Indicator | Alella | Group median | Position |
|---|---|---|---|
| Tropical nights a year, today | 41 nights | 10 nights | higher than 85 % of them |
| Tropical nights a year, 2050 | 98 nights | 48 nights | higher than 88 % of them |
| Average summer maximum, 2050 | 28,7 °C | 32,4 °C | lower than 76 % of them |
| Night-time heat island | 1,0 °C | 0,4 °C | higher than 84 % of them |
| Flood-prone area (100-year) | 0,0% | 1,2% | lower than 85 % of them |
| Area burnt 2016-2026 | 0,3% | 0,0% | higher than 74 % of them |
| Water stress 2050 (0-5) | 4,9 | 4,8 | higher than 54 % of them |
| Maximum 50-year gust | 27 m/s | 30 m/s | lower than 78 % of them |
| Ground movement | −1,2 mm/yr | −0,6 mm/yr | sinking faster than 78 % of them |
| Population aged 65 or over | 22% | 20% | higher than 70 % of them |
Compared with the 311 municipalities in Barcelona province. The bar shows where Alella stands: further right means more risk.
| Indicator | Alella | Group median | Position |
|---|---|---|---|
| Tropical nights a year, today | 41 nights | 2 nights | higher than 88 % of them |
| Tropical nights a year, 2050 | 98 nights | 46 nights | higher than 89 % of them |
| Average summer maximum, 2050 | 28,7 °C | 30,9 °C | lower than 94 % of them |
| Night-time heat island | 1,0 °C | 0,3 °C | higher than 74 % of them |
| Flood-prone area (100-year) | 0,0% | 0,0% | lower than 72 % of them |
| Area burnt 2016-2026 | 0,3% | 0,0% | higher than 89 % of them |
| Water stress 2050 (0-5) | 4,9 | 4,1 | higher than 78 % of them |
| Maximum 50-year gust | 27 m/s | 27 m/s | higher than 50 % of them |
| Ground movement | −1,2 mm/yr | −0,4 mm/yr | sinking faster than 95 % of them |
| Population aged 65 or over | 22% | 20% | higher than 71 % of them |
Compared with the 948 municipalities in Catalonia. The bar shows where Alella stands: further right means more risk.
| Indicator | Alella | Group median | Position |
|---|---|---|---|
| Tropical nights a year, today | 41 nights | 5 nights | higher than 92 % of them |
| Tropical nights a year, 2050 | 98 nights | 51 nights | higher than 94 % of them |
| Average summer maximum, 2050 | 28,7 °C | 31,7 °C | lower than 88 % of them |
| Night-time heat island | 1,0 °C | 0,2 °C | higher than 84 % of them |
| Flood-prone area (100-year) | 0,0% | 0,2% | lower than 77 % of them |
| Area burnt 2016-2026 | 0,3% | 0,0% | higher than 88 % of them |
| Water stress 2050 (0-5) | 4,9 | 4,4 | higher than 82 % of them |
| Maximum 50-year gust | 27 m/s | 27 m/s | lower than 57 % of them |
| Ground movement | −1,2 mm/yr | −0,3 mm/yr | sinking faster than 94 % of them |
| Population aged 65 or over | 22% | 22% | higher than 51 % of them |
Compared with the 8.217 municipalities in Spain. The bar shows where Alella stands: further right means more risk.
| Indicator | Alella | Group median | Position |
|---|---|---|---|
| Tropical nights a year, today | 41 nights | 0 nights | higher than 95 % of them |
| Tropical nights a year, 2050 | 98 nights | 8 nights | higher than 96 % of them |
| Average summer maximum, 2050 | 28,7 °C | 32,4 °C | lower than 82 % of them |
| Night-time heat island | 1,0 °C | 0,1 °C | higher than 91 % of them |
| Flood-prone area (100-year) | 0,0% | 0,6% | lower than 80 % of them |
| Area burnt 2016-2026 | 0,3% | 0,0% | higher than 78 % of them |
| Water stress 2050 (0-5) | 4,9 | 4,6 | higher than 61 % of them |
| Maximum 50-year gust | 27 m/s | 31 m/s | lower than 84 % of them |
| Ground movement | −1,2 mm/yr | −0,4 mm/yr | sinking faster than 85 % of them |
| Population aged 65 or over | 22% | 28% | lower than 73 % of them |
Values for the municipality as a whole (median over built-up land). The position is the percentage of municipalities in the group with a lower value: it is not a probability of damage. 2050 = SSP3-7.0 scenario.
Semicolon-separated tables with a decimal comma, ready to open in a spreadsheet or a GIS (areas include longitude and latitude).
What this is and what it is not. It is a guide-only analysis made with public data and models, with the same rules for every municipality. It does not replace official maps, a technical study or emergency plans. For your own building, look up its report.
Building by building. We have scored the 2.721 Cadastre buildings in Alella with the same rules as each building’s report on Mi Riesgo Climático, from 0 to 100 for each hazard: low (up to 25), medium (up to 50), high (up to 75) and very high.
Aggregates only. To protect each owner, no individual building appears here: only 250 m areas with at least 3 buildings, and neighbourhoods and streets with at least 60 homes.
Wildfire and flooding. Wildfire counts proximity to woodland or scrubland of at least 100 ha (not urban parks or tree-lined streets). For flooding, besides the official flood zones, a building that was inside a real flood observed by satellite (Copernicus EMS, such as the 2024 DANA storm) is at least at high level.
2050. Average for 2041-2070 under an intermediate-to-high emissions scenario (SSP3-7.0). Tropical nights and heat change with the climate; flooding, wildfire, wind and ground movement are shown with current data when there is no projection.
Rivers and streams. Named watercourses from OpenStreetMap. We count the homes less than 50 and 100 m from the watercourse and, separately, how many of them are in an official flood zone (SNCZI). Being close does not mean they will flood, and having no official zone does not mean they cannot.
Neighbourhoods and streets. Neighbourhoods and districts from OpenStreetMap; streets according to the Cadastre address. The street heat index combines tropical nights in 2050 (35 %), heat island (30 %), lack of trees (20 %) and buildings from before 1980 (15 %).
Sources. Cadastre (buildings and addresses); ERA5 + CHELSA/CMIP6 MPI-ESM1-2-HR and AdapteCCa (tropical nights and temperature); Landsat 8/9 and MODIS (heat island); ESA WorldCover and EFFIS (wildfire); MITECO SNCZI (flood zones); JRC (coast); ERA5 + Global Wind Atlas (wind); Copernicus EGMS (ground movement); WRI Aqueduct (water); INE (population); OpenStreetMap, © contributors, ODbL (streets, neighbourhoods, rivers and facilities).