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940:(LT-SEM) clearly show frozen cloud droplets measuring up to 50 μm (0.002 in) on the surface of the crystals. The rime has been observed on all four basic forms of snow crystals, including plates, dendrites, columns and needles. As the riming process continues, the mass of frozen, accumulated cloud droplets eventually obscures the form of the original snow crystal, thereby giving rise to graupel.
990:. In addition, thinner layers of graupel falling at low temperatures can act as ball bearings below subsequent falls of more naturally stable snow, rendering them also liable to avalanche or otherwise making surfaces slippery. Graupel tends to compact and stabilise ("weld") approximately one or two days after falling, depending on the temperature and the properties of the graupel.
888:
As graupel falls, it often deforms into a conical shape. This conical shape, in turn, determines which direction it falls and how far it travels as it falls. Small graupel particles with a base diameter less than 1mm generally fall with the conical base down, but if the particle is between 1mm and
889:
3mm persistent oscillations around the center of the conical base appear, and if larger than 3mm the graupel particle will start to tumble. As the base diameter increases, conical graupel particles generally further horizontally from where it initially fell.
892:
Graupel was formerly referred to by meteorologists as "soft hail." Graupel is distinguishable from true hail in both the shape and strength of the pellet and, in some cases, the circumstances in which it falls. Ice from
1247:
877:
point of water. Contact between a snow crystal and the supercooled droplets results in freezing of the liquid droplets onto the surface of the crystal. This process of crystal growth is known as
757:
986:. The combination of density and low viscosity makes fresh layers of graupel unstable on slopes, and layers of 20–30 cm (8–12 in) or higher present a high risk of dangerous slab
885:. When this process continues so that the shape of the original snow crystal is no longer identifiable and has become ball-like, the resulting crystal is referred to as graupel.
1255:
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The frozen droplets on the surface of rimed crystals are difficult to see even when zoomed in, and the topography of a graupel particle is not easy to record with a
946:
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913:. However, graupel does also occur in thunderstorms. Graupel is also fragile enough that it will typically fall apart when pressed on.
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Chueh, Chih-Che; Wang, Pao K.; Hashino, Tempei (January 2018). "Numerical Study of Motion of
Falling Conical Graupel".
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Precipitation that forms when supercooled droplets of water freeze on a falling snowflake
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1340:. National Oceanic and Atmospheric Administration (NOAA), accessed September 12, 2006.
1338:
Terms used by meteorologists, forecasters, weather observers, and in weather forecasts
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1073:
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1203:
1199:
922:
881:. Crystals that exhibit frozen droplets on their surfaces are often referred to as
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982:, due to its rimed exterior. Macroscopically, graupel resembles small beads of
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in both formation and appearance. However, both hail and graupel are common in
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Graupel commonly forms in high-altitude climates and is both denser and more
901:. Graupel forms fragile, soft, oblong crystals and falls in place of typical
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is formed in hard, relatively uniform layers and usually falls only during
854:
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at temperatures as low as −40 °C (−40 °F), far below the normal
1334:. National Snow and Ice Data Center (NSIDC), accessed September 12, 2006.
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1248:"The Relation of Crystal Riming to Avalanche Formation in New Snow"
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Electron
Microscopy Unit, Beltsville Agricultural Research Center
786:, forming 2–5 mm (0.08–0.20 in) balls of crisp, opaque
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However, observations of snow crystals with a low-temperature
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Graupel pellets in morning, having fallen the previous day
861:. These droplets, which have a diameter of about 10
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865:(0.00039 in) on average, can exist in the liquid
952:
Graupel encasing and hiding a snow crystal from view
734:
728:
1321:. The Weather Channel, accessed September 12, 2006.
722:
1355:
1272:. American Avalanche Association. Archived from
1189:
1298:. Dictionary.com, accessed September 12, 2006.
1045:– term variously used for frozen precipitation
694:
964:Rime on both ends of a columnar snow crystal
782:in air are collected and freeze on falling
1242:
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813:, and at higher elevations as well. The
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873:point as long as above the homogeneous
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1250:. Department of Atmospheric Sciences,
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809:clouds, though graupel also falls in
749:
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909:situations, often in concert with
25:
1385:
1306:Merriam-Webster Online Dictionary
1284:
1110:World Meteorological Organization
1024:
1012:
1007:Snowflakes can turn into graupel
1000:
957:
945:
718:
670:
1289:
1131:"What in the world is graupel?"
1308:, accessed September 12, 2006.
1262:
1236:
1210:
1204:10.1016/j.atmosres.2017.09.008
1183:
1164:U.S. Department of Agriculture
1123:
1092:
1066:
13:
1:
1364:Snow or ice weather phenomena
1350:, accessed December 21, 2008.
1059:
1031:Graupel in shape of snowflake
938:scanning electron microscope
824:
7:
1036:
598:Severe weather terminology
60:Temperate and polar seasons
10:
1390:
1344:About.com Weather Glossary
1217:Graupel - What Is Graupel?
1078:Merriam-Webster Dictionary
993:
1105:International Cloud Atlas
793:Graupel is distinct from
1252:University of Washington
841:Conical graupel particle
925:because of the limited
853:crystals may encounter
1074:"Graupel - Definition"
970:Graupel and avalanches
842:
834:
659:Tropical cyclone terms
35:
1296:3 results for:graupel
1244:LaChapelle, Edward R.
1228:Weather Glossary, G,
917:Microscopic structure
840:
832:
266:Extratropical cyclone
190:Air-mass thunderstorm
33:
1192:Atmospheric Research
817:code for graupel is
626:Weather modification
224:Anticyclonic tornado
1319:Weather Glossary, G
933:in the instrument.
621:Weather forecasting
457:Rain and snow mixed
283:Subtropical cyclone
1330:2014-02-21 at the
1313:Weather glossaries
1222:2012-02-16 at the
1159:"Rime and Graupel"
843:
835:
751:[ˈɡʁaʊpl̩]
677:Weather portal
293:Atlantic hurricane
271:European windstorm
178:Volcanic lightning
139:Cumulonimbus cloud
36:
1080:. Merriam-Webster
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1254:. Archived from
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1168:. Archived from
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200:Dry thunderstorm
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833:Falling graupel
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762:), also called
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1325:All About Snow
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1285:External links
1283:
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1276:on 2010-05-04.
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1290:Dictionaries
1274:the original
1264:
1256:the original
1246:(May 1966).
1238:
1227:
1212:
1195:
1191:
1185:
1174:. Retrieved
1170:the original
1162:
1139:. Retrieved
1134:
1125:
1114:. Retrieved
1103:
1094:
1082:. Retrieved
1077:
1068:
973:
935:
920:
891:
887:
849:conditions,
844:
818:
807:cumulonimbus
792:
768:snow pellets
767:
763:
713:
712:
430:Diamond dust
407:
354:Winter storm
185:Thunderstorm
18:Snow pellets
1054:Ice pellets
984:polystyrene
911:ice pellets
855:supercooled
847:atmospheric
845:Under some
799:ice pellets
776:supercooled
644:Meteorology
579:Meteorology
467:Snow roller
462:Snow grains
425:Ice pellets
374:Snow squall
305:Storm surge
251:Anticyclone
207:Mesocyclone
195:Thundersnow
144:Arcus cloud
1358:Categories
1176:2020-03-23
1141:2022-05-16
1116:2019-09-03
1100:"Glossary"
1060:References
988:avalanches
927:resolution
907:wintry mix
903:snowflakes
875:nucleation
784:snowflakes
638:Glossaries
574:Jet stream
513:Convection
499:Atmosphere
447:Cloudburst
310:Dust storm
276:Nor'easter
246:Fire whirl
241:Dust devil
234:Waterspout
161:Heat burst
156:Microburst
114:Wet season
102:Dry season
1348:About.com
1270:"Graupel"
1230:About.com
1198:: 82–92.
879:accretion
825:Formation
764:soft hail
569:Heat wave
564:Cold wave
508:Chemistry
359:Ice storm
349:Firestorm
261:Polar low
229:Landspout
212:Supercell
173:Lightning
151:Downburst
107:Harmattan
41:Part of
1328:Archived
1220:Archived
1135:KUSA.com
1037:See also
976:granular
871:freezing
859:droplets
780:droplets
440:Freezing
401:Freezing
364:Blizzard
43:a series
1302:Graupel
994:Gallery
747:German:
714:Graupel
594:Extreme
540:Physics
530:Climate
518:Physics
408:Graupel
396:Drizzle
344:Sirocco
327:Monsoon
298:Typhoon
256:Cyclone
219:Tornado
166:Derecho
51:Weather
1112:. 2017
1084:15 Jan
857:water
778:water
602:Canada
557:Season
487:Topics
332:Amihan
320:Haboob
315:Simoom
127:Storms
82:Autumn
77:Summer
72:Spring
67:Winter
1043:Sleet
883:rimed
867:state
815:METAR
805:with
770:, is
607:Japan
535:Cloud
523:River
472:Slush
134:Cloud
1374:Hail
1086:2012
980:snow
929:and
895:hail
851:snow
797:and
795:hail
788:rime
589:List
552:Mist
452:Snow
435:Rain
413:Hail
339:Gale
1200:doi
1196:199
905:in
766:or
547:Fog
1360::
1304:.
1226:.
1194:.
1161:.
1150:^
1133:.
1108:.
1102:.
1076:.
863:μm
821:.
819:GS
790:.
745:;
738:əl
732:aʊ
45:on
1232:.
1206:.
1202::
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1144:.
1119:.
1088:.
741:/
735:p
729:r
726:ɡ
723:ˈ
720:/
716:(
702:e
695:t
688:v
20:)
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