FAQ
General
Why create yet another/a new platform?
Drought is a multifaceted phenomenon. A lot of information is available, but in different places. The idea of the drought platform is to bring together all key information on drought and present it in one place, including data, information, warnings and currently applicable measures. As a result, more efficient drought preparations can be made and its negative consequences minimised.
Several countries have similar platforms. Until now, Switzerland only had one research platform on the subject of drought (drought.ch).
I thought drought only occurred in summer?
We are more familiar with summer drought (often linked to a heatwave), but a drought can also occur in winter. A drought is always the result of a water shortage, regardless of the time of year. Indeed, winter drought (e.g. due to lack of snow) is often the cause of drought later on in the year.
What is the point of the platform?
With clear information and timely warnings, the cantonal and communal authorities, the economic sectors and the public can better prepare for periods of drought. They can set plans in place and introduce suitable measures, thereby preventing or minimising damage
What does the drought index value mean for me in everyday life?
The drought index is an automatically calculated, standardised parameter that provides an integral assessment of the drought situation in each region. However, there can be considerable local variations in the severity of a drought, so values may deviate from the regional drought level.
What should I do if there is a drought?
The local effects of droughts can differ greatly. If a drought occurs, it is therefore important to keep up to date and to follow the instructions of the local authorities.
In the longer term, forward-looking strategies are needed to deal with increasing periods of drought, e.g. adapting agricultural practices and drinking water supply system.
But as is so often the case, the following principle applies here as well: prevention is better than cure. Instead of adapting to increasingly long and more frequent droughts, active climate protection (e.g. through the reduction of emissions that damage the environment) can significantly mitigate the increase in droughts, heat, heavy precipitation and lack of snow.
How do the forecasts differ from those on the MeteoSwiss app?
In contrast to the more familiar weather forecasts for the next few days, long-term forecasts simulate the weather for several weeks. Because long-term forecasts involve a lot of uncertainty, their focus is on forecasting tendencies and trends in the coming weeks and not on individual precipitation events.
Will Switzerland experience more periods of drought going forward?
Yes; climate scenarios for Switzerland show an increase in the frequency and intensity of drought periods by the end of the century. See also CH2018
Impact and measures
Where can I find the measures that apply to my region?
In Switzerland, the cantons and communes are responsible for measures relating to water. Please contact your local authority about to find out about the measures in place.
Do I need to stock up on drinking water?
There is no need to do this to prepare for a possible drought. However, the Federal Office for National Economic Supply recommends that all households have an emergency supply for crisis situations.
What impact do the drought warnings have?
Warnings and recommendations for action in the case of drought
Where can I report my own observations on drought?
Soon it will be possible to report observations directly on the drought platform. Such information helps us greatly to improve and optimise our products.
What restrictions are there/what recommendations should I follow when a drought occurs?
Warnings and recommendations for action in the case of drought
The neighbouring commune has to save water, but we don’t. Why is that?
The need to save water is often based on very specific local conditions.
Warnings
Are drought warnings published on AlertSwiss?
As soon as stability has been achieved in the underlying technology (CAPSuisse), the drought warnings will also be published on AlertSwiss
Can I set up or deactivate push notifications for warnings?
Yes, you can. Instructions can be found here: How to manage the push notifications for warnings in the MeteoSwiss app – MeteoSwiss (admin.ch)
Do the cantons issue drought warnings?
No
Are there specific warnings for individual sectors?
No
What is the difference between drought level and hazard level?
The drought level (1–5) is automatically calculated from the measured and modelled data and updated daily. It provides a general overview of the drought situation. The hazard level (1,2,4), meanwhile, is based on the weekly expert assessment of the current condition and the forecast of the drought level per region. It therefore differs from the automatically calculated drought level in that it is an interpretation of the current and forecast situation. Furthermore, the hazard level is directly linked to a call-to-action.
Why is there no hazard level 3 for drought?
Drought is forecast for a period of 4 weeks using an indicator that takes into account the various drought influencing factors (precipitation, soil moisture, water levels in lakes, rivers and water reservoirs). Because there are a number of influencing factors and a relatively long forecast period of 4 weeks, it is not currently possible to categorise more precisely than into hazard levels 1, 2 and 4. Hazard level 2 (moderate risk, yellow) provides information about an impending dry period, which can have different effects on water bodies, groundwater levels, soil moisture or water resources, depending on its severity. Because drought affects the environment and the water supply in different ways, instructions from the cantonal and regional authorities can already be expected at this level, and water should be used sparingly. Hazard level 4 (considerable risk, red) is indicated if the situation is likely to worsen and have a widespread impact, the public also being affected by restrictions and measures to contain the drought.
Why are the warning regions so large and where is the warning region for my postcode?
The warning regions are based on the existing federal warning regions. As drought typically affects large regions (unlike thunderstorms, for example), these regions closely align with local environmental conditions. Furthermore, It is not (yet) possible to base forecasts on smaller areas, in particular for the hydrological drought index.
What is the relationship between drought warnings and forest fire danger warnings?
Drought and forest fire are treated as two different processes. Drought is a gradual process that may lead to an increase in the risk of forest fires, but does not necessarily do so. Technically speaking, drought only increases the amount of fuel available. When humidity is high, however, the fuel does not become any more flammable, even when the drought is severe. Flammability is therefore a key factor in forest fires, which have a variety of causes (lightning, people, etc.). Rainfall can certainly reduce the risk of forest fires, for example by increasing humidity or moistening the uppermost soil layers, but may not be enough to compensate for severe drought due to deep groundwater and soil layers (deeper than approx. 18 cm, the maximum depth in the Fire Weather Index FWI). But the opposite is also possible: dry surface soils can create a high risk of forest fire, yet there is a low risk of drought, if deep soils and groundwater are at a normal level. Even one-off or brief weather events can have a short-term positive or negative effect on the forest fire risk, but not dryness (e.g. wind, sunlight on bare ground in spring, etc.).
When is there a major risk of drought?
A high risk of drought typically arises when the following conditions occur simultaneously over a longer period of time:
-
- Below-average precipitation: If there is less precipitation than usual over a longer period of time, this can lead to a shortage of water resources.
- High evaporation: High temperatures and dry air can lead to increased evaporation, so water resources are depleted more rapidly.
- Low water reserves: When existing water reserves in lakes, rivers or reservoirs are low, there is an increased risk of drought as less water is available to meet the needs of the public, agriculture and industry.
- Long periods of heat: The demand for water increases during hot spells, both for human consumption and to irrigate agricultural land. If there is insufficient rainfall to meet this increased demand, drought conditions may develop.
- Water requirements in agriculture: In agricultural areas, water requirements may be particularly high during the plant growth period. This can lead to a drought if there is not enough rain or irrigation systems do not function adequately.
Data
Why are there no data on water use?
In Switzerland, water resource oversight is organised on a cantonal level. The cantons issue licences for water use and are responsible for enforcing water protection laws. There is no national oversight of water use, although this would be beneficial in some circumstances, in particular with regard to irrigation in agriculture.
It is recognised that there is a need to improve the collection of data on water. Several projects are currently being run to close the data gap.
Federal Council strategy for adaptation to climate change in Switzerland
Why is the data from cantonal discharge measuring stations not taken into account for national drought monitoring?
Currently, data from two cantonal discharge monitoring stations are considered: Reppisch-Dietikon (ZH572) and Jona-Rüti (ZH582). More cantonal stations will be added going forward, as these often better reflect small water bodies, which are generally more affected by drought. However, there needs to be reliable operational data delivery. Work on this is ongoing.
Why are some FOEN discharge monitoring stations not included?
Only those measuring stations that are most representative (and as uninfluenced as possible) for the specific warning regions were selected to calculate the drought index.
What happens with data from heavily influenced discharge measuring stations?
Some stations were deliberately excluded from the drought index calculation because discharge at these sites is too strongly impacted (e.g. by water abstraction, backwater or installations). To counteract this, data from some cantonal stations on smaller waterbodies were also considered on a selective basis. However, this does not entirely overcome the problem. Efforts are being made to include additional cantonal data, e.g. from smaller watercourses, which are less affected. But this will take some time, as all this data must first be obtained and checked, and then an operational data flow set up.
Where do the data come from?
Precipitation data: MeteoSwiss
Discharge/water level data: Federal Office for the Environment
Modelled soil moisture data: Federal Office for the Environment
Satellite data: swisstopo
How are forecasts with probabilities to be interpreted?
Modelled predictions are always subject to a certain degree of uncertainty. Probabilities help to quantify this uncertainty and give an idea of how likely a prediction is to occur.
Why is no drought index displayed when measurement data is missing?
The drought index is calculated on the basis of a range of variables (precipitation, discharge, soil moisture). If the values for one of these variables are missing, the drought index cannot be calculated.
How is the drought index calculated?