Author Institution: Department of Geography, California State University ; Department of Geography, Santa Ana CollegeVarious snow dune forms were observed and photographed on frozen Lake Erie at Marblehead, Ohio, in January 1982. The dune field contained several dune types. The barchan was the most common form; seif and triangular dunes were also sighted. Conditions necessary for dune formation included winds from a constant direction and a flat ice surface. Dunes were not seen on the ice where pressure ridges existed

Hannes, Gerald P.

Hannes, Susan M.

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Copyright © 1984 Ohio Acad. Sci. OO3O-O95O/84/OOO1-OO51 $2.00/0OBSERVATIONS OF SNOW DUNES ON LAKE ERIE1GERALD P. HANNES, Department of Geography, California State University, Fullerton, CA 92634SUSAN M. HANNES, Department of Geography, Santa Ana College, Santa Ana, CA 92706ABSTRACT. Various snow dune forms were observed and photographed on frozen LakeErie at Marblehead, Ohio, in January 1982. The dune field contained several dunetypes. The barchan was the most common form; seif and triangular dunes werealso sighted. Conditions necessary for dune formation included winds from a con-stant direction and a flat ice surface. Dunes were not seen on the ice where pressureridges existed.OHIOJ. SCI. 84(1): 51-54, 1984INTRODUCTIONDepositional features formed in sandhave been studied extensively in recentyears (Bagnold 1941, Lancaster 1980,Worrall 1974). However, few articles havebeen published on forms produced byblowing snow. There appears to be a simi-larity between the sand and snow forms ofeolian deposition. An early study by Cor-nish (1914) attempted to describe thesesimilarities. He attributed this likeness inform to atmospheric eddy structures. Morerecently, Langham (1981), Kind (1981),and Schmidt (1982) have reviewed theliterature on snow deposition, drifts, andsnow forms. Doumani (1967) and Rikhter(1945) outlined the classification of snowdrift forms and described the factors caus-ing variation in these features. Rikhterestablished 3 categories: barchans, wave-like configurations, and other forms. Manyof the references pertaining to snow driftforms have been related to studies con-ducted in the Antarctic (Moss 1938) whilefew have dealt with snow forms on theGreat Lakes (Hannes and Hannes 1982).OBSERVATIONS AND DISCUSSIONMETEOROLOGICAL CONDITIONS. Weatherdata from the Marblehead Coast GuardStation (4l°32'30"N, 82°43'30"W) wereobtained (table 1). A light snow coveredthe ice on Lake Erie on 25 January 1982.'Manuscript received 5 July 1983 and in revisedform 11 October 1983 (#83-26).Winds were generally from the north, butno dunes were formed on that day. By theafternoon and late evening of 26 January(1100-2300), the winds had shifted to thewest-southwest and southwest. Air tem-peratures at this time were still below freez-ing. However, no dunes were observed on26 January. Figs. 1, 2, and 3 were takenin the mid-afternoon of 27 January be-tween 1300 and 1430 LST. Early on27 January (0500), the winds had shiftedto the south. This southerly flow persistedapproximately 16 hours before shifting tothe south-southwest. The wind speedvaried from 4.6 to 7.7 m/sec throughoutthe morning and early afternoon, generallyhigher than the previous day. Air tempera-tures ranged from — 3.9 to —2.2 C duringthe afternoon hours. The snow dunesformed when the wind was constant indirection. This is in agreement with theconditions for the formation of barchandunes in sand (Bagnold 1941) and ice(Moss 1938). On the evening of 27 Januaryat 2300, the winds generally increased inspeed and shifted to the south-southwest.This continued through 28 January. Thehigher velocities coupled with increasingair temperatures caused the ice to breakup on 28 January, destroying the snowdune field.LAKE ERIE SNOW DUNES. According toBagnold (1941), windblown deposits in-clude drifts and true dunes. Unlike themore common snow drifts of the northernOhio area, dunes can exist independently5152 G. P. HANNES AND S. M. HANNES Vol. 84TABLE 1Meteorological data for 26, 27, and 28 January 1982,at Marblehead Coast Guard Station.Local WindStandard Wind SpeedTime Direction (m/sec)Air Tem-perature(C)wwWNWWNWwwswwswwswwswswswswof obstacles such as rocks, vegetation, andbuildings. On 27 January 1982, snowdunes were observed and photographedon Lake Erie at Marblehead, Ohio. Thephotographs were taken on the headlandwhich forms the easternmost portion ofthe Marblehead Peninsula (fig. 4). Theviews are generally looking in southerlyand southeasterly directions towards theFIGURE 1. Snow dune field on Lake Erie lookingsouth-southeast towards the mouth of Sandusky Bay.FIGURE 2. Barchan dunes.FIGURE 3- Seif and other dune forms.mouth of Sandusky Bay. Several duneswere seen on the frozen lake, as shown infigs. 1,2, and 3, including barchans, seifdunes, interlocking barchans, triangulardunes, and irregular forms. The dune fieldcovered an area of approximately 650 ha onLake Erie and extended into Sandusky Bay.OhioJ. Sci. LAKE ERIE SNOW DUNES 53While being photographed, the duneswere being built by saltation, the processby which snow particles are picked up andtransported by the wind with intermittentcontact with the ice. This is best observedin fig. 1. According to Kind (1981), salta-tion is generally confined to a thin or shal-low layer above the surface. Deposition ofsnow is then brought about by boundarylayer turbulence (Langham 1981).Perhaps the most common form ob-served in the dune field was the barchan, orcrescent-shaped feature with tips or hornspointing downwind (fig. 2). According toDoumani (1967), the shapes of snow bar-chans can be quite variable. Generally,snow barchans are less crescentic in shapethan sand dunes. The estimated size of theLake Erie barchans was from 2.7 to 3.6 min length, 1.8 to 2.4 m in width (or fromhorn—to—horn), and less than 0.6 m inheight. Also visible is the lee face of thebarchan (fig. 2). Doumani (1967) suggeststhat snow dunes differ from sand dunes inthat the latter have a true slip face whereasthe former do not. There is very little slip-page on the lee side of a snow dune, andtherefore no true slip face exists. This lackof a slip face suggests that the migration ofbarchan snow forms is different than thatof sand.Barchan dunes are excellent indicators ofwind direction since their horns pointdownwind. For example, fig. 2 is lookingtowards the southeast. The winds areMarblehead Peninsula. OhioFIGURE 4. Location of the study area in northernOhio.blowing from the south (or right side);therefore, the horns are on the left sides ofthe barchans. In fig. 1, south is at theupper right corner; the snow appears to besaltating diagonally across the photograph.Triangular dune forms also appear in thephotographs, particularly in fig. 1. Theywere generally smaller in size than the bar-chans. Triangular forms may represent theerosion of existing barchans or possibly theformation of new barchans. Enough obser-vations were not taken to support or refutethis possible relationship to barchans.Seif forms were also visible near theshoreline where the topography likelycaused a multidirectional wind pattern(fig. 3). As described by Bagnold (1941)and reaffirmed by Lancaster (1980), seifsand dunes evolve over time through thetransformation of barchan dunes. The hori-zontally trending snow dune just below thecenter of fig. 3 illustrates the seif formdiagramed in Lancaster's article. It appearsas 2 modified barchans joined by the elon-gation of one of the horns of the upwinddune. Apparently, snow seifs conform toBagnold's hypothesis on their formation asa variation in the wind field operates onbarchan forms.No dunes formed along the northernshore of the Marblehead Peninsula. Smallpressure ridges, ice jams, and other surfaceirregularities were noted in the areas free ofdune forms. Therefore, the dunes devel-oped only where the ice surface was ex-tremely flat. It is also interesting to reportthat no dunes were created on a large, flat,unvegetated exposure of limestone rockless than 1.0 km west of the dune field.Perhaps the topography of the Peninsula aswell as the trees surrounding the limestoneexposure modified the wind flow patterns.The physical nature of the flat surface —ice versus rock — may also be a factor.Dunes formed by blowing snow aretherefore generally similar to those ofblowing sand. They are ephemeral featuresrequiring very specific snow properties,surface conditions, and wind character-istics. Where the ice was smooth at the54 G. P. HANNES AND S. M. HANNES Vol. 84easternmost tip of the Marblehead Penin-sula, winds blowing from the south createdthe dune field.LITERATURE CITEDBagnold, R. A. 1941 The physics of blown sandand desert dunes. Methuen Co., London. 265 p.Cornish, V. 1914 Waves of sand and snow.Unwin Brothers, Ltd., London. 383 p.Doumani, G. A. 1967 Surface structures insnow. In: H. Oura (ed.), Physics of snow and ice.Inst. Low Temp. Sci., Hokkaido Univ., Japan.p. 1119-1136.Hannes, G. P. and S. M. Hannes 1982 Lake Eriesnow dunes. Weatherwise 35: 278-279.Kind, R. J. 1981 Snow drifting. In: D. M. Grayand D. H. Male (eds.), Handbook of snow. Per-gamon Press, New York. p. 338-358.Lancaster, N. 1980 The formation of seifdunes from barchans — supporting evidence forBagnold's model from the Namib Desert. Z.Geomorph. 24: 160-167.Langham, E.J. 1981 Physics and properties ofsnow cover. In: D. M. Gray and D. H. Male(eds.), Handbook of snow. Pergamon Press, NewYork. p. 275-329.Moss, R. 1938 The physics of an ice-cap. Geogr.J. 92: 211-231.Rikhter, G. D. 1945 Snezhnyi pokrov, ego gor-mirovanie i svoista (Snow cover, its formation andproperties). Izv. Akad. Nauk. SSSR Moscow(English transl. by U.S. Army Snow, Ice, Perma-frost Res. Est., Transl. 6).Schmidt, R. A. 1982 Properties of blowingsnow. Rev. Geophys. Space Phys. 20: 39—44.Worrall, G. A. 1974 Observations on somewind-formed features in the southern Sahara.Z. Geomorph. 18: 291-302.

Observations of Snow Dunes on Lake Erie

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Observations of Snow Dunes on Lake Erie

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