Show simple item record

dc.contributor.advisorChairperson, Graduate Committee: Jordy Hendrikxen
dc.contributor.authorMarienthal, Alex Graysonen
dc.date.accessioned2015-06-18T13:58:04Z
dc.date.available2015-06-18T13:58:04Z
dc.date.issued2014en
dc.identifier.urihttps://scholarworks.montana.edu/xmlui/handle/1/8786en
dc.description.abstractSnow avalanches are a potentially fatal and highly destructive natural hazard. Snow slab avalanches occur in steep alpine terrain due to an unstable layered snowpack. When a consolidated layer of snow forms a slab above a weak layer of snow the slab may collapse and slide downhill due to gravitational and applied forces (e.g., the weight of a skier, explosive, or new snowfall). Persistent weak layers form in the snowpack due to strong vapor pressure gradients, and they can last for weeks to months as a slab builds above them. Avalanches on persistent weak layers become less frequent, yet are typically larger and more destructive the longer and deeper the layer is buried. Deep slab avalanches on persistent weak layers pose a difficult forecasting problem due to their low likelihood of occurrence and potentially high consequences. This thesis aims to identify meteorological metrics that are associated with deep slabs on persistent weak layers. We used univariate analysis, classification trees, and random forests to explore relationships between seasons with deep slabs and summaries of meteorological metrics over the beginning of the season during weak layer formation. We also looked at the relationship between days with these avalanches and summaries of meteorological metrics over the days prior to them. In addition, we reviewed a case study of a season that had multiple deep slabs on a persistent weak layer and a historic wet slab avalanche cycle on the same layer, at Bridger Bowl ski area. Seasons with deep slabs typically had relatively low precipitation throughout the early part of the season (i.e., November - January), and a snowpack in the beginning of the season that was sufficiently deep, but shallow enough for a weak layer to develop. Our results also showed warmer twenty-four hour temperatures and more precipitation over seven day prior to days with dry deep slabs, and extended periods of above freezing temperatures were seen prior to days with deep wet slabs. These results are in line with previous research and are suggestive of meteorological summaries that may be useful to forecast deep slab avalanches on persistent weak layers.en
dc.language.isoenen
dc.publisherMontana State University - Bozeman, College of Letters & Scienceen
dc.subject.lcshAvalanchesen
dc.subject.lcshForecastingen
dc.subject.lcshDepth hoaren
dc.subject.lcshWeatheren
dc.titleMeteorological metrics associated with deep slab avalanches on persistent weak layersen
dc.typeThesisen
dc.rights.holderCopyright 2014 by Alex Grayson Marienthalen
thesis.catalog.ckey2733375en
thesis.degree.committeemembersMembers, Graduate Committee: Karl W. Birkeland; Kathryn Irvineen
thesis.degree.departmentEarth Sciences.en
thesis.degree.genreThesisen
thesis.degree.nameMSen
thesis.format.extentfirstpage1en
thesis.format.extentlastpage209en
mus.data.thumbpage76en


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record


MSU uses DSpace software, copyright © 2002-2017  Duraspace. For library collections that are not accessible, we are committed to providing reasonable accommodations and timely access to users with disabilities. For assistance, please submit an accessibility request for library material.