WeMOI and NAOi influence on major avalanche activity in the Eastern Pyrenees

García-Sellés, Carles; Peña, Juan Carlos; Martí, Gloria Novel; Oller, Pere; Martínez, Pere

doi:10.1016/j.coldregions.2010.08.003

Cited by 24 publications

(19 citation statements)

References 27 publications

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“…Keylock (2003) first established a connection between the positive phase of NAO and snow avalanches in Iceland, and postulated that the recent rise in NAO could have implications on return periods and runout distances. García et al (2009) and García-Sellés et al (2010) found a negative relationship between avalanche activity and the NAO in the Eastern Pyrenees, but could not identify the process of the NAO governing avalanche activity. However, in the French Alps, no correlations were found between avalanche activity and the NAO (Jomelli et al, 2007).…”

Section: Introductionmentioning

confidence: 85%

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Large‐scale teleconnection patterns and synoptic climatology of major snow‐avalanche winters in the Presidential Range (New Hampshire, USA)

Martin

Germain

2017

Intl Journal of Climatology

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The relationships between the synoptic climatology, large‐scale teleconnections and the regional avalanche activity index (RAAI) inferred from tree‐rings were evaluated for the Presidential Range in the White Mountains (New Hampshire, USA). During the period 1936–2012, 18 years of regional avalanche activity were compared with the winter‐scale prevailing joint temperature/climatic modes (cold/wet (CW), cold/dry (CD), warm/wet (WW) and warm/dry (WW)), the North Atlantic Oscillation (NAO), the El Niño‐Southern Oscillation (ENSO), the 500‐mbar composite anomaly maps and the ratio of snow from different storm tracks. The total winter snowfall and the NAO negatively correlate with the RAAI. There is also a significant difference in avalanche activity between winters with a NAO under or above −3. Winters of regional avalanche activity were present in the four climatic modes, albeit the ratio of avalanche/non‐avalanche years is superior for CW winters compared to the three other modes, as well as for wet winters compared to dry winters. CW, CD and WW winters exhibit a negative NAO anomaly, which is eastbound for the wet years. Cold winters (CW, CD) receive more snow from the Great Lakes, whereas coastal depressions are more important during wet winters (CW, WW). The NAO is an adequate predictor of snowfall, but does not provide information about the storm tracks. On the contrary, the ENSO is poorly correlated with snowfall, but its relationship is significant with the ratio of snow produced by coastal depressions (positive relationship) and Great Lakes storms (negative relationship). These are the first results quantifying the atmospheric circulation – synoptic meteorology – snow avalanche relationships in Northeastern North America.

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Section: Introductionmentioning

confidence: 85%

“…() and García‐Sellés et al . () found a negative relationship between avalanche activity and the NAO in the Eastern Pyrenees, but could not identify the process of the NAO governing avalanche activity. However, in the French Alps, no correlations were found between avalanche activity and the NAO (Jomelli et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Large‐scale teleconnection patterns and synoptic climatology of major snow‐avalanche winters in the Presidential Range (New Hampshire, USA)

Martin

Germain

2017

Intl Journal of Climatology

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“…For example, it is not sufficient to cluster the years with high avalanche counts and a CI around 1980 since they are scattered throughout the period of study due to the high interannual variability. A possible interesting further work would be to relate these results to synoptic patterns such as annual NAO anomalies, as already pointed out in other regions (Keylock, 2003;Garcia-Sellés et al, 2010). This approach also opens the door to the possible evaluation of the future impact of climate change on avalanche activity in the French Alps by combining the regression models obtained with the results of SCM simulations forced by scenarios of climate warming, as in a study conducted by Jomelli et al (2009) for debris flows in the Ecrins massif.…”

Section: Discussion Outlooks and Conclusionmentioning

confidence: 99%

Snow and weather climatic control on snow avalanche occurrence fluctuations over 50 yr in the French Alps

Castebrunet

Eckert²,

Giraud

2012

Clim. Past

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Abstract. Snow avalanche activity is controlled to a large extent by snow and weather patterns. However, its response to climate fluctuations remains poorly documented. Previous studies have focused on direct extraction of trends in avalanche and winter climate data, and this study employs a time-implicit method to model annual avalanche activity in the French Alps during the 1958-2009 period from its most representative climatic drivers. Modelled snow and weather data for different elevations and aspects are considered as covariates that explain actual observed avalanche counts, modelled instability indexes, and a combination of both avalanche activity indicators. These three series present relatively similar fluctuations over the period and good consistency with historically harsh winters. A stepwise procedure is used to obtain regression models that accurately represent trends as well as high and low peaks with a small number of physically meaningful covariates, showing their climatic relevance. The activity indicators and their regression models seen as time series show, within a high interannual variability, a predominant bell-shaped pattern presumably related to a short period of colder and snowier winters around 1980, as well as a very slight but continuous increase between 1975 and 2000 concomitant with warming. Furthermore, the regression models quantify the respective weight of the different covariates, mostly temperature anomalies and south-facing snowpack characteristics to explain the trends and most of the exceptional winters. Regional differences are discussed as well as seasonal variations between winter and spring activity and confirm rather different snow and weather regimes influencing avalanche activity over the Northern and Southern Alps, depending on the season.

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“…This period, variable in time, prepares the conditions that can favour MA 738 activity. These situations can also be identified indirectly using a cumulative NAO index (CNI), which exhibits a closer 739 relationship to avalanche activity than the standard index (Keylock, 2013;García-Sellés et al, 2010). This preparatory 740 process was not considered in the present work when classifying the MAE, only the atmospheric patterns triggering MAE 741 were considered.…”

Section: Spatial Analysis 679mentioning

confidence: 99%

“…Climate varieties identified by García et al, 2007. 113 In 1990 the study area was divided into 8 nivological regions (NR) for operational forecasting (García et al, 1996). In 1994 114 these regions were reduced to 7 (Figure 1).…”

Section: Study Area 89mentioning

confidence: 99%

Characterizing major avalanche episodes in space and time in the twentieth and early twenty-first centuries in the Catalan Pyrenees

Oller

Muntán

García-Sellés

et al. 2015

Cold Regions Science and Technology

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8With the aim of better understanding avalanche risk in the Catalan Pyrenees, the present work focuses on the analysis of 9 major (or destructive) avalanches. For such purpose major avalanche cartography was made by an exhaustive 10 photointerpretation of several flights, winter and summer field surveys and inquiries to local population. Major avalanche 11 events were used to quantify the magnitude of the episodes during which they occurred, and a Major Avalanche Activity 12Magnitude Index (MAAMI) was developed. This index is based on the number of major avalanches registered and its 13 estimated frequency in a given time period, hence it quantifies the magnitude of a major avalanche episode or winter. 14 Furthermore, it permits a comparison of the magnitude between major avalanche episodes in a given mountain range, or 15 between mountain ranges, and for a long enough period, it should allow analysis of temporal trends. Major episodes from 16 winter 1995/96 to 2013/14 were reconstructed. Their magnitude, frequency and extent were also assessed. During the last 17 19 winters, the episodes of January 22-23 and February 6-8 in 1996 were those with highest MAAMI values, followed by 18 January 30-31, 2003, January 29, 2006, and January 24-25, 2014. To analyze the whole twentieth century, a simplified 19 MAAMI was defined in order to attain the same purpose with a less complete dataset. With less accuracy, the same 20 parameters were obtained at winter time resolution throughout the twentieth century. Again, 1995/96 winter had the highest 21 MAAMI value followed by 1971/72, 1974/75 and 1937/38 winter seasons. The analysis of the spatial extent of the different 22 episodes allowed refining the demarcation of nivological regions, and improving our knowledge about the atmospheric 23 patterns that cause major episodes and their climatic interpretation. In some cases, the importance of considering a major 24 avalanche episode as the result of a previous preparatory period, followed by a triggering one was revealed. 25 Key words 26Major avalanche, major avalanche episode, Pyrenees, magnitude, frequency, hazard, risk.

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WeMOI and NAOi influence on major avalanche activity in the Eastern Pyrenees

Cited by 24 publications

References 27 publications

Large‐scale teleconnection patterns and synoptic climatology of major snow‐avalanche winters in the Presidential Range (New Hampshire, USA)

Large‐scale teleconnection patterns and synoptic climatology of major snow‐avalanche winters in the Presidential Range (New Hampshire, USA)

Snow and weather climatic control on snow avalanche occurrence fluctuations over 50 yr in the French Alps

Characterizing major avalanche episodes in space and time in the twentieth and early twenty-first centuries in the Catalan Pyrenees

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