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Snow zones map - France

What are the French snow zones ?

On the map of the national annex, the French territory is divided by canton into five regions of snow identified from A to E. Three of these regions (A to C) are subdivided into two to account for accidental snow precipitation.

Zone A1 A2 B1 B2 C1 C2 D E
Characteristic value of snow on the ground without elevation sk,0 0.45kN/m2 0.45kN/m2 0.55kN/m2 0.55kN/m2 0.65kN/m2 0.65kN/m2 0.90kN/m2 1.40kN/m2
Design value of exceptional snow load on the ground sk,0 - 1.00kN/m2 1.00kN/m2 1.35kN/m2 - 1.35kN/m2 1.80kN/m2 -

Eurocodes - Snow zones map - France (2011-2021) Snow zoning of France (2011-2021)
The French overseas departments, overseas territories and overseas collectivities are not subject to snowfall except Saint Pierre and Miquelon.
Characteristic value of snow on the ground without elevation at Saint Pierre and Miquelon: sk,0 = 2.60kN/m2.

How to determine the influence of elevation on the ground snow load in France ?

Two distinct variation laws must be applied depending on whether the construction is in snow zone E or not.
Snow loads are calculated as follows:

How to adjust the ground snow load according to return period in France ?

Pn is the annual probability of exceedence :
dwl is the design working life, in years. Look at the design working life of buildings in France.

V is the coefficient of variation of annual maximum snow load with V=0.2 for a recurrence interval less than 50 years and V=0.6 for a recurrence interval greater than 50 years.

It should not be applied for annual probabilities of exceedence greater than 0,2 (i.e. return period less than approximately 5 years).

Example of results given by the software

See the features of Eurocodes Zoning for snow analysis in France
Available in English/French, otherwise «Google Translate»!

B1 - Localization

French flag
3.5332° , 45.7153°
741482m , 6512993m
Large map
Simple map
D 304A, 63120 Sauviat, Auvergne-Rhône-Alpes

B2 - Elevations

Elevation map to calculate orography factor
Distances / Direction At the place of construction 500m 1000m
North 436 m 360m 407m
Northeast 405m 465m
East 456m 473m
Southeast 419m 446m
South 449m 476m
Southwest 432m 411m
West 360m 468m
Northwest 403m 452m

B3 - Building

monumental building

B4 - Terrain categories

Terrain map
Sectors 1 2 3 4
Categories IIIa IV IV IV
Radius R of the angular sector : 593m

C1 - Snow NF EN 1991-1-3/NA (may 2007) + A1 (july 2011)

A2 (sk,0 = 0.45kN/m2)
sk,436m = 0.686 kN/m2

s100ans = 0.774 kN/m2

sad = 1.0kN/m2

C2 - Wind NF EN 1991-1-4/NA (march 2008) + A1 (july 2011) + A2 (september 2012) + A3 (april 2019)

2 (vb,0 = 24.0m/s)
Sectors 1 2 3 4
Sector definition from 35° to 125° from 125° to 215° from 215° to 305° from 305° to 35°
Fundamental value of the basic wind velocity vb,0 24.0m/s
Shape parameter K 0.2
Exponent n 0.5
Annual probability of exceedence p 0.01
Probability factor cprob 1.038
Directional factor cdir 0.7 1.0 1.0 1.0
Basic wind velocity vb 17.4m/s 24.9m/s 24.9m/s 24.9m/s
Reference roughness length z0,II 0.05m
Roughness length z0 0.2m 1.0m 1.0m 1.0m
Terrain factor kr 0.209 0.234 0.234 0.234
Height above ground z 15.0m
Minimum height zmin 5.0m 15.0m 15.0m 15.0m
Roughness factor cr(z) 0.904 0.635 0.635 0.635
Orography factor* co(z) 1.0 1.0 1.0 1.0
Mean wind velocity vm(z) 15.8m/s 15.8m/s 15.8m/s 15.8m/s
Turbulence factor kl 0.97 0.854 0.854 0.854
Standard deviation of the turbulence σv 3.544m/s 4.989m/s 4.989m/s 4.989m/s
Turbulence intensity Iv(z) 0.225 0.315 0.315 0.315
Air density ρ 1.225kg/m3
Exposure factor ce(z) 2.102 1.292 1.292 1.292
Peak velocity pressure qp(z) 392.0N/m2 491.5N/m2 491.5N/m2 491.5N/m2
Peak wind velocity for Serviceability Limit States vp(z),SLS 91.1km/h 102.0km/h 102.0km/h 102.0km/h
Peak wind velocity for Ultimate Limit States vp(z),ULS 111.5km/h 124.9km/h 124.9km/h 124.9km/h
* Here, the orography factor is calculated according to Procedure 1, for an orography consisting of obstacles of various heights and shapes. This type of orography is the most frequently encountered.However, if the building is in a case of orography consisting of well individualized obstacle (isolated hills and ridges or cliffs and escarpments) the orography factor must be calculated according to the procedure 2. According to EN 1991-1-4 §4.3.3(1), the calculated orography factor (1.018) is not taken into account because it does not increase wind velocities by more than 5%.

C3 - Seism Code of the Environment - Article D563-8-1 (09/01/2015) + JORF n°0248 of 24/10/2010 text N°5

3 (1.1m/s2)
Sauviat, Puy-de-Dome (63)
A seismic analysis is required for this building.