ROS-analyse
A ROS-analyse (risk and vulnerability analysis) is a statutory assessment of hazards that can affect a plan area or a construction project. It is anchored in the Planning and Building Act § 4-3 and is required as part of all zoning plans, municipal master plans and individual cases where the building ground may be exposed to natural hazards or human-made events. The ROS-analyse is the collecting document for where flooding, landslides, quick clay, noise, pollution, fire and civil protection conditions have been mapped and assessed in a planning process.
The ROS-analyse follows a standardised method developed by Direktoratet for samfunnssikkerhet og beredskap (DSB, the Norwegian Directorate for Civil Protection) and rests on a systematic split between probability and consequence. For each identified hazard, a qualitative or semi-quantitative assessment is made, often presented in a colour-coded risk matrix. Findings with high probability and/or serious consequence must be followed up in the plan with concrete measures: safety zones, building lines, a requirement for geotechnical documentation before a building permit, or a direct ban on measures in the exposed area. The probability classes are typically 1-5 (from "very unlikely" to "very likely"), and the consequence classes follow the same scale across the dimensions life/health, material assets and the environment.
The data basis for a modern ROS-analyse draws in awareness maps and thematic data from several sector authorities. NVE supplies maps for flooding, landslides and quick clay. Direktoratet for mineralforvaltning (the Norwegian Directorate of Mining) contributes mineral rights and potential mine openings. Miljødirektoratet (the Norwegian Environment Agency) gives access to contaminated ground. The municipality's own data covers fire, vulnerable infrastructure and critical societal functions. Bringing these layers together on the same zoning map is the core task of the analysis.
For a developer, the ROS-analyse has three practical consequences. It governs where and how you can build within the plan area, and it can trigger requirements for cost-driving measures (retaining walls, drainage, geotechnical ground surveys). It sets the premises for insurance premiums and the bank's credit assessment. And it forms the documentation basis in any later dispute about inadequate risk handling. A thorough ROS-analyse at an early stage reduces both project risk and later complaints.
In Placepoint you can visualise many of the source data that go into a ROS-analyse: flood, landslide and quick clay awareness, contaminated ground, groundwater and geological conditions at the same matrikkel level.
How the dataset appears on the map
The dataset is part of the map layer Risk as Flood areas, flood protection areas, and flood events:
From Placepoint's glossary: ROS-analyse
More information: DSB: ROS-analyse, Lovdata: Planning and Building Act § 4-3, NVE: Awareness maps.
English: Risk and vulnerability analysis (ROS-analyse). The statutory hazard assessment required for Norwegian zoning plans under the Planning and Building Act § 4-3.
Common questions
When is a ROS-analyse required by law?
For all new zoning plans and municipal master plans under the Planning and Building Act § 4-3. It is also required in municipal emergency preparedness plans under the Civil Protection Act and in certain building cases with particular risk exposure.
Which hazards must be assessed?
Natural hazards (flooding, quick clay, landslides, storm surge), human-made events (accidents, fire, sabotage), and societal events (power cuts, pandemic). Climate risk is mandatory from 2024.
Where do I find the data that goes into it?
Awareness maps from Norges vassdrags- og energidirektorat (NVE), Norges geologiske undersøkelse (NGU) and Direktoratet for samfunnssikkerhet og beredskap (DSB) are the primary source. In Placepoint they sit under the Risk category and can be shown in one operation for the relevant plot.
What happens if the analysis is missing?
A missing ROS-analyse is grounds for objection from statsforvalteren (the county governor, formerly fylkesmannen) and Sivilforsvaret (the Norwegian Civil Defence), and it can stop the plan from being adopted. Existing plans without a full ROS are a typical legal due diligence flag when buying a plot.