雪氷チーム

Snow and Ice Research Team

急激な気象変化に伴う雪崩災害に対する道路管理の判断支援に関する研究
Study on a Road Management Technology to Support Decision-Making on Avalanche Disasters Resulting from Rapid Changes in Weather
近年、気候変動に伴う激甚化した気象災害や大規模災害による影響が懸念されています。積雪寒冷地の北海道でも、多量降雪後の大雨や気温の急激な上昇による影響が現れており、これらに伴う雪崩による被害が発生しています。
雪氷チームでは、防災地質チームと協力して、厳冬期における多量降雨などの急激な気象変化に伴う雪崩災害に対して、冬期道路交通の安全性確保を図り、道路管理を支援する手法の開発に取り組んでいます。
In recent years, there have been concerns about the adverse effects of the more extreme meteorological disasters and large-scale disasters
that are associated with climate change. Even in Hokkaido, which is a snowy cold region, heavy rainfall and rapidly rising air temperatures
after heavy snowfall have caused avalanches that have brought considerable damage.
The Snow and Ice Research Team, in cooperation with the Geological Hazards Research Team, has been developing technologies tosupport winter road management. The technologies will ensure the safety of road traffic against avalanche disasters caused by sudden
weather changes, such as heavy rainfall in midwinter.

厳冬期の多量降雨による雪崩災害事例
Example of avalanchedisasters caused byheavy rainfall in midwinter

斜面積雪の安定性評価手法の提示

Presenting a technology for assessing the stability of snow cover on slopes
積雪内部の雨水や融雪水の移動過程と積雪底面からの流出過程を明らかにすることを目的として、現地調査や数値解析を行います。
これらの結果から、厳冬期の大雨や急激な気温上昇に伴う斜面積雪の安定性評価手法を検討します。
We will conduct onsite surveys and numerical analyses to clarify the movement processes of rainwater and snowmelt water inside
the snow cover and at the bottom of the snow cover when the water runs off. Based on the results of the surveys and analyses, wewill examine a technology for evaluating the stability of snow cover on slopes at times of heavy rainfall and rapidly rising airtemperatures in midwinter.
厳冬期の平地Flat area in midwinter

厳冬期の斜面
Slope in midwinter

降雨Rainfall

日射Insolation

融雪期の斜面
Slope in the snowmelt period

透 tion

浸 aの infiltr
水 ter

気温上昇

Rising air temperatureWa

雪 eltm

融now
S

局所的に水みち(矢印)が形成され、水は地面に到達。

Localized water paths(arrows) form, and the waterreaches the ground surface.

水は、ほぼ鉛直に浸透して地面に到達。

水は、傾斜した積雪層に沿って、斜面下方に流れる。

積nowc

層る
す水S

retWa

帯

The water infiltrates nearlyvertically and reaches theground surface.

The water flows down theslope along the sloped snowlayers.

雪 overgrin
abeerlay

出流と水

ret
Waingrabedanrelay

積雪の強度低下
Decrease in the strengthof the snow cover

帯の面

↓

底

▲色水を使った積雪内部の水分移動に関する現地調査例
Example of onsite survey for water movement inside the snow cover using colored water

積雪下の土砂の安定性評価手法の提示

ffnour

thet
aomtt
bo

雪崩発生
Avalanche occurs▲降雨や気温上昇による雪崩の発生過程の概念図
Conceptual diagram for the occurrence ofan avalanche caused by rainfall and rising air temperatures

Presenting a technology for assessing the stability of soil under the snow coverWe will conduct onsite surveys, lab experiments, and numerical analyses to clarify theprocesses of infiltration and movement of rainwater and snowmelt water inside the snow coverand of runoff to the ground. Based on the results of these activities, we will examine
technologies for evaluating the stability of soil under the snow cover.

Development of technology to support decision-making on road management regarding avalanche disasters
降雨量や融雪水量などを用いた厳冬期の大雨や急激な気温上昇に伴う雪崩災害の発生条件を明らかにすることを目的として、過去の雪崩事例解析を行います。
この結果と、斜面積雪の安定性評価手法および積雪下の土砂の安定性評価手法に基づいて、雪崩災害に対する道路管理の判断支援手法を検討します。
We will conduct analyses of past avalanche disasters to clarify the conditions under which avalanche disasters
caused by heavy rainfall and sudden rises in air temperature occur in midwinter. For these analyses, we will use
rainfall, the amount of snowmelt water, and other data. We will examine technologies for supporting
decision-making in road management when avalanche disasters occur based on the analysis results, technologies
for assessing the stability of the snow cover on slopes, and the stability of the soil under the snow cover.
斜面積雪のクラックの発生例

Example of a crack
in the snow cover on the slope

湿雪表層雪崩の発生例

Example of a wet-snow
surface avalanche

湿雪全層雪崩の発生例

Example of a wet-snow
full-depth avalanche

Wet snow avalanche: A phenomenon in which snow containing water slides down the slope
Surface avalanche: When the sliding surface is within the snow coverFull-depth avalanche: When the sliding surface is the ground surface
Slush avalanche: An avalanche in which snow containing large amounts ofwater flows down the slope

降雨量

雪崩災害に対する道路管理の判断支援手法の開発

湿 雪 雪 崩 ：水を含んだ雪が斜面を流下する現象
表 層 雪 崩 ：すべり面が積雪内部
全 層 雪 崩 ：すべり面が地面
スラッシュ雪崩：大量の水を含んだ雪が流動する雪崩

Rainfall

雨水や融雪水の地盤への浸透や移動および湧出の過程を明らかにすることを目的として、現地調査や室内実験、数値解析を行います。
これらの結果から、積雪下の土砂の安定性評価手法を検討します。

スラッシュ雪崩
Slush avalanche

湿雪雪崩

Wet snow avalanche

融雪水量 Amount of snowmelt water▲雪崩発生条件（イメージ）
Conditions under which avalanches occur (Concept)
2022.7

安全・快適北の道

Safe, pleasant driving on Northern Roads

国立研究開発法人土木研究所 寒地土木研究所

National Research and Development Agency Public Works Research Institute Civil Engineering Research Institute for Cold Region