Observations of snowpack ripening in the Sierra Nevada, California, U.S.A.

Abstract

ABSTRACT. Th e transiti o n from a dr y, sub-freezing snow cover to isotherm a l snow fr eely co nduc ting water was obse ryed near timbe rlin e in the Sie n a Nevada, Ca liforni a, U.S.A. Although th ere we re fe w m aj o r strati g r a phi c bo und a ri es in th e sno w pa c ks obse n 'ed, minor tex tural di sco ntinuiti es were sufficient to bo th ro ute wa ter la te r a ll y downslope a nd la ter create ice layer s a t these stra ta . During th e fi rst few days of snowm elt, down slope m ovem ent of water p a rallel to th e stra ta all owed wa te r to bypass lowe r laye rs of the snow cove r o n slopes a nd conve rge in mic ro to pog raphic d e prcss ions on leve l terra in, creating isola ted drains throug h the snowpac k. In additi o n to th ese drains, fl o w lingers associa ted with holes in th e ice sheets delive red water to the b ase o f the snow seve ra l d ays prior to the tho rough we ttin g o f th e snow p ac k. Form ati on of a se ri es of ice lenses just below the snow surface eve ry nig ht released much more latent hea t th a n did ice-laye r d evelopment within the bulk of th e snowpac k or a t its base.

Contact spectroscopy for determination of stratigraphy of snow optical grain size

“…At depth, the same complexes of ice layers and large OGRs at depths of 150-170 and 120-135 cm occurred. Below these layers, OGRs were consistently $50 mm larger than in April except at distinct ice and larger grain layers from melt infiltration through flow fingers and layer pooling at textural discontinuities (Kattelmann and Dozier, 1999).…”

An evaluation of the hydrologic relevance of lateral flow in snow at hillslope and catchment scales

“…The transformation from vertical flow to lateral, or slope‐parallel flow is commonly assumed to occur in and on soils. Lateral flow, however, can also occur in sloping snowpacks (Wankiewicz, ; Singh et al , ; Kattelmann and Dozier, ; Peitzsch, ; Whitson, ). Despite an early recognition by hydrologists of the occurrence of lateral flow through snow (Horton, ; Horton, ), its hydrologic significance at hillslope and catchment scales has received little attention.…”

“…Snowpacks are typically composed of layers of snow from multiple storms with spatially and temporally variable properties (Gustafsson et al , ). Layer boundaries can create the hydraulic conductivity contrasts necessary for impeding vertical flow (Seligman, ; Gerdel, ; Wankiewicz, ; Woo et al , ; Marsh and Woo, ; Schneebeli, ; Singh et al , ; Kattelmann and Dozier, ; Waldner et al , ; Peitzsch, ; Whitson, ; Williams et al , ).…”

“…Indeed, ice layers can have permeability five to ten times lower than the surrounding snowpack (Albert and Perron, ). However, lateral flow has also been observed in snow with no prominent ice layers (Wankiewicz, ; Kattelmann and Dozier, ; Waldner et al , ; Whitson, ). Kattelmann and Dozier () noted that some ice layers have the appearance of ‘swiss cheese’ with 50–75% of total ice area composed of holes.…”

“…However, lateral flow has also been observed in snow with no prominent ice layers (Wankiewicz, ; Kattelmann and Dozier, ; Waldner et al , ; Whitson, ). Kattelmann and Dozier () noted that some ice layers have the appearance of ‘swiss cheese’ with 50–75% of total ice area composed of holes. Such ice layers tend to route water laterally only for short distances before concentrating water into vertical channels (Gerdel, ; Gerdel, ; Jordan, ; Marsh and Woo, ; Furbish, ).…”