Avalanche cartography in Europe (Same project)

Results of the enquiry about avalanche cartography in the same project

(by Montserrat Mases i Coberó and Glòria Martí i Domènech ICC Barcelona - Spain)

RESULTS OF THE ENQUIRY ABOUT AVALANCHE CARTOGRAPHY IN THE SAME PROJECT

In the SAME Project (Snow Avalanche Mapping and Warning in Europe) an enquiry of avalanche cartography has been sent to different European laboratories. The main objective of the enquiry is to determine the state of the art in avalanche mapping database and zoning in Europe and to provide an:

· Inventory of different systems in use in different partner countries, including digitised data bases

· Inventory and typology of different kinds of avalanche maps

· Inventory of avalanche zoning procedures.

The answers received are:

Andorra- One answer received from Andorra government.

Austria- Two answers received from Innsbruck (FBVA.ILWL) and Graz (TUGRAZ.INW).

Spain- Two answers received from Catalonia GC.DPT.ICC and Zaragoza (ITGE).

France- Two answers received from CEMAGREF

Iceland- Three answers received from IMOR.AS. Three kinds of maps: event map, maximum extent map, evacuation maps.

Italy- Five answers received. Two from Veneto, two from Trento and one from Lombardia.

Norway- One answer received from NGI.

Switzerland - Two answers received: One from Davos (SFISAR) including information about three kinds of maps; Communal avalanche hazard maps, a cantonal avalanche atlas (Scale 1:25.000) and various avalanche path maps. The second answer was from local avalanche observation authority of the Bernese Alps region in Interlaken.

DIFFERENT KIND OF AVALANCHE MAPS IN EUROPE

From the enquiries received the maps have been classified into 8 types.

1) Avalanche paths maps

a) French type

The countries that use this cartography are:

*Country, region*	*Name*	*Scale*
ANDORRA	Cartografia de localització probable d'allaus	1:25000, 1:10000
ARAGÓN (Spain)	Mapa de peligrosidad de aludes	1:25000, 1:5000
CATALONIA (Spain)	Mapa de zones d'allaus	1:25000
FRANCE	Carte de localisation probable des avalanches	1:25000, 1:20000
ITALY	Carte di localizzazione probabile delle valanghe	1:25000, 1:5000

- Methodology : The process is standard (photointerpretation and surveys of the population). Models are not used to determine runout distance except in France where proofs with models are carried out.

- Information : in the document the outline of avalanches is represented.

The map shows in orange the avalanche paths determined by photointerpretation and field observation, and in violet the paths determined by surveys of the population. If there is coincidence of both observations, the colour of avalanche path is the superposition of orange and violet. This means that in these maps there is a double entrance of information, which in many occasions is complementary. In the map the snow-drift erosion zones, the snow-drift deposition zones and the cornices can also be represented.

- Use :

Country region	Scientific	Land planning	Risk management	Protection studies	Authorisation	Judicial use
ANDORRA	Yes	Yes	Yes	Yes	Yes	Yes
ARAGÓN (Spain)	Yes	Yes	No	Yes	No	No
CATALONIA (Spain)	Yes	Yes	No	No	No	No
FRANCE	Yes	Yes	Yes	Yes	No	Yes
ITALY	Yes	Yes	No	No	No	No

-Legislation : Only France and Andorra have a legislation related to avalanche paths maps. Some Italian regions (i.e.: Lombardia) are preparing a law concerning to avalanche paths maps.

b) Icelandic type (project) .

*Country, region*	*Name*	*Scale*
Iceland	Actual and probable avalanche path maps	?

-Methodology : enquiry, field observation, expert assessment.

-Information: They include the observed and potential avalanche paths.

2) Hazard maps

*Country, region*	*Name*	*Scale*
AUSTRIA	Hazard Zone Map-Klostertal/Austrian Avalanche and Torrent Control	> o equal a 1:2000
FRANCE	Risk Map	de 1:10000 a 1:1000
ITALY	PZEV	?
Switzerland	Communal avalanche hazard maps	1:10000 and 1:15000

- Methodology : mathematical models, expert and remote systems are used with avalanche cadastre data where the outline of avalanches are represented. These models allow to determine the extent of avalanche paths.

Field observations and nivo-meteorological data are essential in this methodology.

Information : The terrain surface is divided into zones with different danger rate. Lines dividing the zones depend on the avalanche impact pressure and their periodicity.

The legend is standard. There are four danger rates represented by different colours.

Red: very dangerous zones. The red zones are:

A- Avalanches with impact pressures over 30 kN/m² or more, with a frequency less than 300 years.

B- Avalanches with less impact pressures, with a frequency less or equal than 30 years. In this area people are in death danger and buildings can be destroyed.

Blue: Impact pressure is less than 30 kN/m² and frequency from 30 to 300 years. Zones with powder snow avalanches are signalled in blue when the impact pressure is over 3 KN/m² and frequency is less than 30 years.

Yellow: Zones located in the powder snow avalanches trajectory with impact pressure less than 3 kN/m² and frequency more than 30 years.

Zone where the avalanches are rare (frequency more than 300 years).

White: Zones without avalanches.

- Use :

Country, region	Scientific	land planning	Risk management	Protection studies	Authorisation	Judicial use
AUSTRIA	Yes	YES	YES	YES	YES	YES
FRANCE		YES	YES	YES	YES	No
ITALY	YES	YES	No	No	No	No
SWITZERLAND	No	YES	YES	YES	YES	YES

-Legislation : In Austria, Switzerland, France and Andorra maps are used in law.

i.e.. In Switzerland the avalanches are included in forest and land planning laws. In France they are included in housing, land planning and environment laws. In Italy there aren’t avalanche laws but some regions have begun to write laws related to the avalanches.

In Norway the areas drawn in the hazard map have to be investigated in more detail before house building or other landuse. The information is public.

3) Maximum extent map

*Country, region*	*Name*	*Scale*
Iceland	Maximum extent map	1:5000, 1:10000 and 1:15000
NORWAy	Historical registration maps	1:5000

- Methodology : The icelandic maps are made from field observations, archive consulting, and expert systems. The norwegian maps are based on eye witnesses, testimonies, historical records and sayings, church books and field observations shortly after avalanche events or later (summer) field studies of damage to the forest etc.

- Information : The icelandic map presents the maximum extent of known avalanches. The information is divided into three classes depending on the information accuracy. In the norwegian map lines show outer extension of the avalanches with year of event.

- Use :

Country, region

Scientific

Land planning

Risk management

Protection studies

Authorisation

Judicial

use

ICELAND

YES

NORWAY

YES

-Legislation : The map isn’t provided for in regulation.

4) Avalanche maps

*Country, region*	*Name*	*Scale*
ICELAND	Avalanche maps	1:5000, 1:10000 and 1:15000

- Methodology : They are made from field observations archive consulting, and expert systems.

- Information : collection of recent avalanches. Sometimes it includes the historic avalanches.

- Use :

Country, region

Scientific

Land planning

Risk management

Protection studies

Authorisation

Judicial

use

ICELAND

Yes

-Legislation : It isn’t provided for in regulation.

5 ) Evacuation maps

*Country region*	*Name*	*Scale*
ICELAND	Evacuation map	1:5000, 1:10000

- Methodology : They are made from field observations, archive consulting, and expert systems.

- Information : They display the three levels of evacuation used by IMO (Icelandic Meteorological Office) and significant avalanches

- Use :

Country, region

Scientific

Land planning

Risk management

Protection studies

Authorisations

Judicial

use

ICELAND

Yes

-Legislation : Evacuation is regulated by the law and the evacuation levels signalled in the map.

6 ) Snow avalanche maps

*Country, region*	*name*	*Scale*
NORWAY A	Army snow avalanche maps	1:50000
NORWAY B	Hazard maps	1:50000

- Methodology : The fist is produced by the army. Made from digital terrain models, from field observations archive consulting, and expert systems. Sometimes testimonies are used.

- Information : In the first map are represented the avalanche paths. Two colours are used: a) Starting zones (with dangerous aspect) in red and b) Runout zones (terrain lying below starting zones, which may be exposed to avalanche) in pink.

In the second map there is information about other hazards. Red zones shows areas that can potentially be reached by all kinds of slides (snow avalanches, rock slides, debris flows and slushflows)

- Use :

Country, region

Scientific

Land planning

Risk management

Protection studies

Authorisation

Judicial

use

NORWAY A

Yes

NORWAY B

Yes

-Legislation : There are no regulations associated with the map but it is adapted to the scale of avalanche danger. For official use only (not public).

7) Avalanche atlas

*Country, region*	*Name*	*Scale*
SWITZERLAND	Avalanche Atlas of canton Uri	1:25000

- Methodology : They are made from field observations, testimonies, remote systems and field evaluation.

- Information : Known avalanche release.

- Use : They are used to elaborate danger maps

Country, region

Scientific

Land planning

Risk management

Protection studies

Authorisation

Judicial

use

SWITZERLAND

Yes

-Legislation : They have legal authority.

8) Hazard line maps

*Country, region*	*Name*	*Scale*
NORWAY	Detailed hazard line maps	1:5000

- Information: With lines showing probable maximum avalanche runout to be reached every 100, 333 and 1000 years. Depending on the client’s wish, maps that show all kinds of slides are sometimes produced.

- Use:

Country, region

Scientific

Land planning

Risk management

Protection studies

Authorisation

Judicial

use

NORWAY

Yes

ABSTRACT ABOUT AVALANCHE CARTOGRAPHY. (Answers received from different laboratories).

In the next paragraphs we present an abstract of different answers to the enquiry. The percentages are calculated from all the enquiries received from different laboratories and organisms.

In some countries the central government produces the avalanche cartography i.e.: France, Norway, Andorra, Iceland Spain (Aragón). In other countries the regions develop the cartography. I.e.: Italy, Switzerland, Austria, Spain (Catalonia).

Every theme such as scale, data organisation, legislation, type of information, use and availability is commented.

Avalanche maps scale.

Different scales are used in Europe. More than a half of countries use two (or more) different scales.

The most used scale are: 1/25.000 and 1/10.000. With less frequency 1/50.000, 1/5.000 and 1/1.000.

Data organisation

Around 65 % of the maps are organised in Geographic Information Systems. The countries which don’t use GIS are: some regions of Italy, some cantons of Switzerland, and France. At present France tries to integrate the GIS Arc-Info.

The most frequent GIS is Arc-Info.

Legislation

Judicial role of maps.

Around 58% of maps have legal implications. There is complete authority of the map in: Austria, France, Switzerland and Andorra. With partial authority: Iceland (Depending on the kind of map), Italy (depending on the region). The only country without legal regulation is Spain.

The legal protection is showed in the next figure. In 36 % of cases, the avalanche map has no legal implication. In 32% of the cases the map has complete authority. There is no such authority in Norway and spain. Depending on the kind of map there is legal authority in Iceland, and in some regions of Italy. There is total legal authority in Austria, Switzerland, France and Andorra.

Around 26% of countries, there are directives or set requirements whom the laws are adapted.

Official use of maps

The avalanche maps can be used in land planning, in building construction, public works and closing, opening roads etc. In Norway the avalanche maps are not used in land planning. In Spain and Italy it depends on the regions. In Austria, Switzerland, Iceland and Andorra the avalanche maps are used in land planning.

There are several judicial uses of avalanche maps in Europe. In Norway and Spain the maps have not judicial use. In Italy depends on the regions. In Austria, France, Switzerland and Andorra the avalanche maps have judicial use.

Type of mapped information.

Delimitation of zones

The kind of mapped information is variable. The most frequent is the outline of avalanches, which is used in the avalanche path maps.

Field observations

In the majority of the maps field observations are used. In Norway only the models are used in avalanche cartography. In Iceland the evacuation map is realised without field observations.

The three next figures show the percentage of the countries that mapped every event avalanche limit, the utmost avalanche limit, and the paravalanche works.

Model use (See [0])

The countries which always use models are Norway (topographic models. See [1]) and Austria (numerical models for powder and wet avalanches). France, Switzerland and Iceland sometimes use models. In France models developed by Cemagref are used (wet snow avalanche models and powder avalanche models). In Iceland to carry out the Evacuation maps two kinds of models are used: topographic ( a- b) (See [1]) and the PCM (See [2]) sliding block model. In Switzerland the Voellmy-Salm model is used. Italy and Spain don’t use models to generate avalanches map.

[0] Harbitz, C.B., 1998 : A survey of computational models for snow avalanche motion. Norvegian Geotechnical Institute, report 581220-1.

[1] Bakkehoi, S., Domaas, U. & Lied, K., 1983 : Calculation of snow avalanche runout distance. Annals of Glaciology, Vol. 4, S. 24-29.

[2] Perla, P.I., Cheng, T.T. & McClung, D.M., 1980 : A two parameter model of snow-avalanche motion. Journal of Glaciology, Vol. 26, Nº 94, p. 197-207.

[3] Salm, B., Burkard, A. & Gubler, H.U., 1990 : Berechnung von Fliesslawinen. Eine Anleitung für den Praktiker mit Beispielen. Mitteilungen des Eid. Institutes für Schnee- und Lawinenforschung, Nr. 47.

Expert’s assessment

In all the presented maps expert’s assessment is used, in particular field observations.

On the other hand only a half of laboratories use aerial photography and satellite photographs.

In the maps where models are used, the results are tested with terrain data only in 26% of cases.

In 32% of maps there is negotiation with those responsible from the mountain management (regional or local authorities) before finishing the map.

Map’s use

The presented avalanche maps are used in the four fields questioned.

Around 95% of the cases use the avalanche maps in land planning, except evacuation map of Iceland. In all enquired European countries there are one kind of avalanche map used in land planning as a minimum.

The majority of maps are used in a scientific studies except the snow avalanche maps of Norway, the Communal maps of Switzerland, and the evacuation maps of Iceland

Data availability

In all enquired countries there are one public map as a minimum, except in Norway.

The other kind of private maps are: the Communal maps of Switzerland, the Arabba maps (Italy), the Graz maps (Austria) and the risk maps of Cemagref (France).

Technical means of distribution

The more frequent technical mean of distribution is paper. At present a lot of organisms can distribute the data in digital files. Distribution via the Internet is used only by the 20% of the organisations involved in the enquiry.