Snow and ice risk
Characteristic of its Mediterranean climate, winter in Montpellier is on average "mild", with no more than 10 days of black ice and/or snowfall. However, this phenomenon can have major consequences for networks, especially roads.
Adopt the right reflexes
From November 15 to March 15, a winter watch is activated as part of the Document d'Organisation de Viabilité Hivernale (D.O.V.H).
The D.O.V.H enables the rapid mobilization of Metropolitan and City of Montpellier services to clear snow from the main traffic arteries, in particular those serving rescue centers and health establishments with emergency services, and the city center
The application of this plan should enable traffic difficulties to be resolved within a reasonable timeframe for the most common inclement weather conditions.
Before
- Inform yourself of the risks and safety instructions
- Prepare the minimum equipment (battery-powered radio, drinking water supply, personal papers, medication, ...)
During
- Inform yourself of the situation.
- Postpone your travel.
- Do not expose your children to danger by picking them up from school. A pick-up service is available in schools.
- Be cautious and vigilant if you have to travel, and use public transport instead.
- Find out about traffic conditions from the regional road information and traffic center (CRICR) or Bison Futé
- Respect the traffic restrictions and detour in place.
- Ease the passage of road and freeway clearance machines, in particular by parking your vehicle outside the traffic lanes.
- Protect yourself from falls and others by clearing snow and salting sidewalks in front of your home, while avoiding blocking water drainage manholes.
- Under no circumstances touch fallen electrical wires.
- Must install generators outside buildings
- Don't use appliances not intended for this purpose (stoves, braziers, etc.) or auxiliary heaters with continuous combustion to heat your home (these appliances should only be used intermittently)
- Think about clearing snow and salt from in front of your home or business... As stipulated in municipal bylaw VAR2018-5354, it's up to you to clear snow and salt in front of your home. This civic and collective act ensures the safety of pedestrians on sidewalks.
After
- Alert the authorities of any danger (18 or 112)
Snow and ice risk in Montpellier
Over the past 30 years, the Hérault département has recorded an Index de Viabilité Hivernale (IVH) of 9 days on average where road operating difficulties have been noted. The intensity of snowfall in the area corresponds to a low snowfall zone. Normal snowfalls range from 2 cm/h to 3 cm/h, but do not exceed 5 cm/h, giving a total fall height of 20 cm.
A snowfall of just a few centimetres can:
- Seriously disrupt or even block road, tramway, air and rail traffic. This snow is easily evacuated by road traffic, but it can also melt and refreeze in the form of icy patches. The formation of black ice or icy patches renders the road network impassable and increases the risk of accidents.
- Provoke damage to infrastructure and trees, caused by overloading caused by accumulating snow.
- Provoke a risk of power lines breaking.
How are snow and ice formed?
Snow is generally formed by the condensation of water vapor in the upper layers of the atmosphere and then falls to the ground more or less rapidly, depending on its structure.
- If the flakes encounter only layers of air with temperatures < 0°C as they fall, the crystals clump together and combine to form increasingly large flakes. These crystals fall to the ground, at relative speeds of 1 to 2 cm/second, forming a layer of snow, or stratum on the ground.
- If the flakes encounter a warm layer of air as they fall from the clouds, the crystals melt and become raindrops. Combined with a near-ground temperature < 0°C, the droplets in an unstable state of supercooling will freeze onto any object to form a layer of the ice. This phenomenon is known as "freezing rain". Fog can also form ice.