Poromoko la theluji (pia banguko, kwa Kiingereza: avalanche) ni kiasi kikubwa cha theluji au barafu kinachoanza kusogea kwenye mtelemko wa mlima na kuteleza au kuanguka kuelekea bondeni. Mwendo wa masi kubwa unaweza kusukuma miamba, miti na chochote kilichopo njiani kwenye mtelemko wa mlima na kuongeza banguko. Poromoko la theluji ni hatari kwa watu waliopo mlimani na pia kwa vijiji bondeni ambavyo vinafikiwa na banguko kubwa. Katika Alpi za Ulaya takriban watu 100 hufariki kila mwaka kutokana na maporomoko ya theluji. Kwenye Andes za Peru watu 4,000 waliuawa na poromoko kubwa la theluji tarehe 11 Januari 1962. Poromoko la theluji lilitelemka kutoka mlima Huascaran na kufunika mji wa Yungay; mengine yalianguka katika mto na kusababisha mafuriko. Tazama pia Miporomoko ya ardhi Marejeo

Runtuhan salji merupakan pergerakan salji yang laju dan secara tiba-tiba menuruni cerun, terjadi disebabkan faktor semula jadi atau aktiviti manusia. Biasanya terjadi di pergunungan, runtuhan salji dapat mencampurkan udara dan air dengan salji yang turun. Pembentukan Kebanyakan runtuhan salji berlaku secara spontannya semasa ribut disebabkan penambahan salji yang turun. Sebab-sebab semula jadi yang lain termasuk hujan, gempa bumi, runtuhan batu and runtuhan ais. Pencetus runtuhan buatan manusia termasuk aktiviti meluncur salji sama ada dengan kenderaan atau individu, dan kerja letupan terkawal. Terdapat tanggapan di kalangan orang ramai mengenai cetusan runtuhan salji disebabkan bunyi kuat, namun perkara ini tidak benar kerana tekanan yang dihasilkan daripada gelombang bunyi adalah terlalu kecil. Pencegahan Terdapat langkah-langkah pencegahan yang dilakukan di kawasan di mana runtuhan salji boleh mengancam nyawa penduduk seperti di resort ski, bandar-bandar di pergunungan, jalan raya serta landasan kereta api. Bahan letupan digunakan secara meluas untuk tujuan ini dengan mencetuskan runtuhan salji kecil...

An avalanche is a natural disaster linked to snow. When there is too much snow on a mountain, some of the snow may fall, causing damage to things in its path. This is called an avalanche. People talk about avalanches because they may be dangerous to skiers and other people doing winter sports. Large avalanches may carry stones, boulders and trees with them. They may bury people under them. If the people are not found rapidly enough by rescue teams they will die of suffocation (not getting enough air) or of hypothermia (freezing cold). The chance of surviving an avalanche is as follows: 92% if found within 15 minutes 30% if found within 35 minutes (victims die of suffocation) nearly zero after two hours (victims die of injuries and hypothermia) European avalanche risk table In Europe, the avalanche risk is widely rated on the following scale, which was adopted in April 1993 to replace the earlier non-standard national schemes. Descriptions were last updated in May 2003 to enhance uniformity pdf Archived 2005-04-17 at the Wayback Machine. [1] Stability: ...

Ang pagguho ng yelo ay ang dagsa, sagasa, o ragasang pagbagsak at pagbulusok ng malalaki at maramihang mga tipak ng bato o kaya natitibag na putol ng mga namuong tubig o niyebe mula sa itaas ng isang bundok. Sa wikang Ingles, tinatawag itong avalanche o snowslide na kadalasang tumutukoy sa isang tipak na pinagsamang niyebe na nakalatag sa isang mas mahinang bahagi ng niyebe at bumigay at dumulas paibaba sa isang matarik na lugar pagkatapos itong gumuho. Ang mga pagguho ng yelo ay kadalasang nangyayari dahil sa pagbigay ng patong-patong na niyebe o snowpack (slab avalanche) kapag masyado ng bumigat ang mga niyebe o kahit lamang sa paglaki ng sakop nito (loose snow avalanche). Pagkatapos nito, ang mga pagguho ng yelo ay kadalasang mas bumibigat at dumarami habang ito ay pababa nang sobrang bilis. Kapag ang pagguho ng yelo ay may sapat ng bilis, ang ilan sa mga niyebe nito ay humahalo sa hangin na nagiging pulbos na pagguho ng yelo o powder snow avalanche na isang uri ng paggalaw na sanhi ng grabidad. Ang mga tipak ng bato o debris na mahahalintulad sa paggalaw ng niyebe ay maaaring tawaging ...

The numerical formulation of a one-dimensional physical snowpack model is presented. The model is operationally employed on a day-to-day basis by avalanche warners to predict snowpack settlement, layering, surface energy exchange and mass balance. Meteorological data obtained from automatic weather stations positioned near avalanche starting zones is used as model input. In this paper, the one-dimensional equations governing the heat transfer, water transport, vapour diffusion and mechanical deformation of a phase changing snowpack are stated. New snow, wind drift and snow ablation are treated as special mass boundary conditions. Snow is modelled as a three-component (ice, water, air) porous material capable of undergoing large irreversible viscous deformations. Phase changes between the components are simulated. Snow layers are defined not only in terms of height and density, but also microstructure. That is, by the size, shape and bonding of the grains composing the ice lattice. The governing differential equations are solved using a fully implicit Lagrangian Gauss-Seidel finite-element method. Example calculations from the catastrophic avalanche winter 1999 are presented to document model performance. The overall mass balance evaluation shows that the model accurately predicts the build-up and ablation of the seasonal alpine snowcover.

Why did one of the worst avalanches in living memory destroy the village of Galtur in February 1999?

Mountain forests provide natural protection against avalanches. They can both prevent avalanche formation in release zones and reduce avalanche mobility in runout areas. Although the braking effect of forests has been previously explored through global statistical analyses on documented avalanches, little is known about the mechanism of snow detrainment in forests for small and medium avalanches. In this study, we investigate the detrainment and braking of snow avalanches in forested terrain, by performing three-dimensional simulations using the material point method (MPM) and a large-strain elastoplastic snow constitutive model based on critical state soil mechanics. First, the snow internal friction is evaluated using existing field measurements based on the detrainment mass, showing the feasibility of the numerical framework and offering a reference case for further exploration of different snow types. Then, we systematically investigate the influence of snow properties and forest parameters on avalanche characteristics. Our results suggest that for both the cold and warm snow parameterized in our simulations, the detrainment mass decreases with the square of the avalanche front velocity before it reaches a plateau value. Furthermore, the detrainment mass significantly depends on snow properties. It can be as much as 10 times larger for warm snow compared to cold snow. By examining the effect of forest configurations, it is found that forest density and tree diameter have cubic and square relations with the detrainment mass, respectively. The outcomes of this study may contribute to the development of improved formulations of avalanche-forest interaction models in popular operational simulation tools and thus improve hazard assessment for alpine geophysical mass flows in forested terrain.

sudden, drastic flow of snow down a steep slope