Avalanche forecast for roads in Iceland - FRIFLYT.NO · Monitored roads • Kirkjubólshlíð: •...

Avalanche forecast for roads in Iceland

Magni Hreinn Jónsson

Åndalsnes, 2017

Monitored roads

• Three monitored roads

• Avalanche forecast made

daily by IMO for the road

administration (IRCA)

• IRCA informs travellers,

issues warnings and closes

roads

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Monitored roads

• Kirkjubólshlíð:

• ~4 avalanches every winter

• In 1-2 cycles

• Súðavíkurhlíð:

• ~27 avalanches every winter

• In ~7 cycles

• Average daily winter traffic: 367 vehicles

• Avalanche forecast since 2013

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Population: 4516

Population: 186

Monitored roads

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• Siglufjarðarvegur:

• ~4 avalanches every winter

• In 4-5 cycles

• Average daily winter traffic: ~200 vehicles

• Avalanche forecast since 2014

• Ólafsfjarðarvegur:

• ~8 avalanches every winter

• In ~5 cycles

• Average daily winter traffic: 368 vehicles

• Avalanche forecast since 2013

Population: 1994

Population: 1348

Súðavíkurhlíð

Monitored roads

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Siglufjarðarvegur, photo: Oddur Sigurðsson

Avalanche forecast

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• Based on statistical analysis of recorded

avalanches and weather measurements

• Likelihood of avalanches for given:

• Wind, Temperature and Precipitation

• Other factors have to be evaluated by the

forecaster:

• Avalanche activity

• Snow depth

• Snow drift

• Snowpack stability

• Etc.

Avalanche forecast

Predefined danger levels:

1. No/minor avalanche danger

within the next 24 hours.

2. Possible avalanche danger

within the next 24 hours.

3. Considerable avalanche danger

(10-40% probability).

4. High avalanche danger (more

than 40% probability).

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Avalanche forecast

Predefined danger levels:

1. No/minor avalanche danger

within the next 24 hours.

2. Possible avalanche danger

within the next 24 hours.

3. Considerable avalanche danger

(10-40% probability).

4. High avalanche danger (more

than 40% probability).

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Súðavíkurhlíð and Kirkjubólshlíð

Avalanche forecast

Predefined danger levels:

1. No/minor avalanche danger

within the next 24 hours.

2. Possible avalanche danger

within the next 24 hours.

3. Considerable avalanche danger

(10-40% probability).

4. High avalanche danger (more

than 40% probability).

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Ólafsfjarðarvegur

Avalanche forecast

Predefined danger levels:

1. No/minor avalanche danger

within the next 24 hours.

2. Possible avalanche danger

within the next 24 hours.

3. Considerable avalanche danger

(10-40% probability).

4. High avalanche danger (more

than 40% probability).

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Siglufjarðarvegur

Avalanche size

…possible avalanches will most

likely be small and should not

reach the road. Conditions are

considered to be at upper limit

of danger level 1.

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Avalanche size

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Avalanche size

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...danger level 1 due to little

snow in gullies...

Monitoring cameras

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Danger level 3 the day before

Danger level 4

Monitoring cameras

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Danger level 1

Warnings and closures

IRCA makes decisions about road closures and issues warnings

Road users can sign up to receive text messages with avalanche warnings for

Súðavíkurhlíð

Started for Ólafsfjarðavegur last winter

Predefined messages:

A. Súðavíkurhlíð: Avalanche hazard possible later today, Wednesday

B. Súðavíkurhlíð avalanches: Alert status is declared today, Wednesday at 11 AM

C. Súðavíkurhlíð avalanches: Danger status is declared today, Wednesday at 12

AM. The road is closed.

D. Súðavíkurhlíð avalanches: Danger status is called off Thursday at 17:30. The

road is open.

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Avalanche defenses

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Avalanche defenses

Ólafsfjarðarvegur, photo: Sveinn Brynjólfsson

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Avalanche defenses

Ólafsfjarðarvegur, photos: Sveinn Brynjólfsson

Conclusion

• Avalanche forecast aims to reduce traffic when the

avalanche danger is increased

• Planned road closures to reduce inconvenience

• …and for safety

• Text messaging service will be started formally this

winter for Ólafsfjarðarvegur

• Improve the forecast to get better consistency between

the roads

21Ólafsfjarðarvegur, photo: Oddur Sigurðsson