Tuesday 8th March Dan Johnson 0845 Leave WISP operations center. The snow falling at NCAR is very heavily rimed dendrite crystals and graupel. On this mission is John Cardwell and Dan Johnson. Hwy. 119 north of Boulder was very icy 45 minutes ago. Now as we drive to the K-band site, solar radiation through the clouds is beginning to melt the ice on the roads and travel is much better. The roads are nearly ice free by the time we arrive at K-band. 0912 ARRIVE AT K-BAND. Snow is falling light to moderately. Crystals falling are very heavily rimed dendrites 1-4 mm diameter. Aggregates are also falling. The winds are SE about 15 mph. Sky is overcast. 0923 Rimed dendrite crystals up to 5 mm diameter. Also observing sector branch crystals 3 mm diameter, some graupel and some aggregates. 0930 Begin the filter sample #1. Filter #559. Flow rate is 1.5 l/min. 0932 Begin chemistry sample #1. 0936 The temperature is -0.5 C. 0938 Snow sample #1 taken (video counter 0-626): Large plate with little plates on edge of large plate Very rimed particle Very rimed dendrite branch 2-3 mm long. Large droplets on branch Huge dendritic branch Rimed plate 1.5 mm dia. with sector plates on end. 0949 Snow sample #2 (video counter 626-1112): Heavily rimed stellar about 2 mm dia. Droplets on stellar about 50 microns dia. Large plate 1.5 mm dia. unrimed Plate 1 mm dia. Drops on plate up to 100 microns dia. Also graupel chunk on side of plate Broken plate 1 mm dia. Half dendrite and a plate 0950 Aggregates falling which are 5 mm diameter. Also falling are heavily rimed crystals which are as large as 5 mm in diameter. 1000 Winds are ESE 10-15 mph. Snow is falling moderately. Temperature is -0.4 C. Aggregates are falling which are 0.5 - 1 cm diameter. Some of the aggregates only have a few crystals on them. Very large dendrites, stellars, and plates also falling with diameters up to 5 mm. 1002 Snow sample #3 (video counter 1112 - ): Needle about 300 microns long Bullet rosette with plates on end Ordinary dendrite heavily rimed. Drops on crystal 30-50 microns dia. Well defined stellar with many drops on branches. Drops are 30-50 microns dia. Needles about 500 microns long with 20 micron dia. drops on it 1007 Snow sample #4 (video counter - 1989): Needles 500-800 microns long Huge dendrite with stellar on end Stellar on its end with 20 micron dia. drops on it Plate 1 mm dia. with a few 20-30 micron drops on it 1015 More aggregates falling now which are 0.5 - 1 cm diameter and crystals the same as at 1000. Snow is falling moderately. Average winds are about 15 mph from the ESE. 1019 Snow sample #5 (video counter 1989-2341): Large plate on end of a branch Large needles 500-1000 microns long Needles with little drops (20 microns dia.) on them 1030 Filter sample #1 is completed. Total flow through filter was 90 l. Chemistry samples #1a and #1b completed. 1031 Begin chemistry sample #2. 1032 Filter sample #2 begins. Filter #581. Flow rate is 1.5 l/min. 1036 Temperature is +1.4 C. Winds ESE 15 mph. Aggregates falling which are made up of heavily rimed dendrites and are < 1.0 cm diameter. Also seeing individual heavily rimed dendrites. 1045 The filter we put out was facing upward unexpectedly. We placed it face down again. 1050 Crystals falling outside visually appear to be smaller now. Snow sample #6 (video counter 2341-2740): Dendrite with needles on it. Needles are 500-1000 microns long Stellar with plates on end. Plate is in center of stellar Large drops on branch up to 100 microns in dia. Many Needles (5-6) and stellar crystals with plates on end. Drops on stellar branches are about 50 microns dia. Plate with very small branches. A few drops on plate Dendrite about 1.5 mm dia. with drops on edges of branch Long needles about 1.5 mm in length 1100 The sun is brighter now and the outline of it can be seen through the clouds. About 1/4 of the sample is needle-like snow which is falling much lighter now. Temperature outside is 1.6 C. 1103 Snow sample #7 (video counter 2740-3103): Bundles of needles Many individual needles Needles with plates and dendrites Very long needles - up to 2 mm in length Plate about 1 mm dia. Needles embedded in dendrite branches 1115 Temperature is 2.0 C. Snow falling very lightly and is made up of heavily rimed spatial crystals. Sun dimly seen through clouds. About 1/3 of crystals appear to be needles. 1130 Chemistry samples #2a and #2b taken. Filter sample #2 finished. Total flow through filter was 87 l. 1134 Chemistry sample #3 begins. 1135 Snow sample #8 (video counter 3103-3597) New film: Little plate inside large broad-branched crystal. Branches are short Needles on the end of a crystal About 6 needles 750 microns in length with approximately 40 micron dia. drops on them Large sector plate crystal 2-3 mm dia. with very little rime Well defined plate 1 mm dia. with no rime Small clumps of needles Plate 2 mm dia. with needles on end 3-D spatial plates with no rime Two large plates on top of each other. Unrimed about 1 mm dia. Broad-branched unrimed crystal about 1 mm dia. Heavily rimed crystal in center of it 1136 Snow falling very lightly. Winds abut 10 mph from the East. Crystals are smaller and there are less aggregates than an hour ago. Crystals have little rime on them at this time. The clouds may have iced up. 1200 Winds east at 10 mph. Just scattered flakes falling. They crystals appear to be a little larger than at 1100. Temperature outside has cooled down to 1.0 C. 1203 Snow sample #9 (video counter 3597-3734): Plates, needles, frozen drop Needle with columns (sheaths) on it? Needle very heavily rimed Plate on top of small broad-branched crystal 1207 The sky is becoming more overcast. Snow is coming down lightly but heavier than at 1200. Snow sample #10 (video counter 3734-4156): Small plates about 500 microns dia. and some particles Heavily rimed plate with needles on top Broad-branched crystal which is very heavily rimed. A 700 micron long needle is in branch. Rime on crystal is made up of 30-50 micron dia. droplets. Heavily rimed plate 400 microns dia. Droplets on plate are 10-20 microns dia. Needle 500 microns in length and rimed. Rimed droplets are very small Ordinary dendrite 3 mm in dia. Very heavily rimed dendrite. Droplets on crystal are 30-50 microns in dia. 1211 Heavily rimed dendritic crystals falling once again. The Electra is overhead. Aggregates are also falling but are small with diameters of 5-10 mm. Individual crystals are as large as 4 mm. Winds are ENE. 1216 Just scattered snowflakes falling. Snow falling is extremely light now. 1221 Snow coming down moderately again - similar to at 1000. Winds are ENE at about 10 mph. 1225 The snow is beginning to fall more heavily now. 1232 Chemistry samples #3a and #3b taken. Chemistry sample #4 begins. 1237 Snow is falling moderately. Winds are ENE. Temperature is 3.2 C. Snow falling is small aggregates about 5 mm diameter and crystals which are heavily rimed. Snow sample #11 (video counter 4156-4448): Stellar dendrite with many needles in branches. Needles are approximately 400 microns long Rimed needles 500-1000 microns in length Group of small plates about 500 microns dia. Two crossed columns on end of dendritic branch Sector plate with rimed needles in branch. Droplets on needles are 20-40 microns dia. Stellar, 1.5 mm dia, with 5-branches (one fell off). There is growth on branches. Clump of needles Needles crossing one another. Possible column on one of the needles. Length of needles are approximately 1 mm. Dendrite 3 mm dia. with heavily rimed clump or graupel particle about 500 microns dia. on top Long hollow needle about 1 mm long 1248 Snow is falling lightly from the NE. 1308 Winds are from the NE. Snow is falling more heavily. We are observing heavily rimed spatial crystals and needles. Also are observing a few heavily rimed columns. 1316 Snow sample #12 (video counter 4448-4565): Thin needles about 1 mm long Stellar about 2 mm dia. rimed with plates on branches Group of needles Column 700 microns long Large bundle of needles Sector plate 2 mm dia. with some riming on branches Large dendrite 3.5 mm dia. with needles embedded in branches Lightly rimed dendrite 3 mm dia. 1324 We copied over approximately 5 min. of the beginning of the video with sample #12 due to a power disturbance. We have corrected the problem. 1332 Chemistry samples #4a and #4b taken. Chemistry sample #5 begins. 1335 Winds are NE at about 5 mph. Snow is falling lightly and is mainly small crystals. Temperature is 2.0 C. 1402 Snow sample #13 (video counter 4565-4670) New film: Needles and planar crystals Big needles or columns (sheaths) Needles and plates 1410 Aggregates falling which are 5-10 mm diameter. Winds NW at approximately 5 mph. Visibility is about 2 miles and has not been greatly reduced since we arrived at K-band. 1412 Snow sample #14 (video counter 4670-5022): Rimed needle Dendrite 2 mm dia. unrimed Stellar 1 mm dia. unrimed Bundles of needles Two stellars and crossing needles Plate 500 microns dia. with large broad-branched crystal below Two well defined dendrites unrimed Graupel particle 1 mm dia. Combination of needles about 400 microns in length 1422 Snow sample #15 (video counter 5022-5080): Capped column 350 microns long 1425 Snow sample #16 (video counter 5080-5234): Long thin needles 1.5 mm in length Very heavily rimed broad-branched crystal - almost graupel Clump of needles next to heavily rimed particle Clumps of columns of sheaths Cluster of needles 1 mm in length Stellar dendrite 1430 Chemistry samples #5a and #5b taken. Chemistry sample #6 begins. 1435 Small crystals falling now which are 0.5-1 mm diameter. The temperature is about 1.7 C. Winds are NE 5-10 mph. There are no aggregates falling. Crystals are very heavily rimed dendrites. There are also some needles and a few columns. 1437 Snow sample #17 (video counter 5234-5345): Two crossed needles 1.5 mm long with 500 micron length column attached to side of it Rimed particle 200 microns dia. on end of unrimed stellar Heavily rimed dendrite 750 microns dia. Irregular-shaped crystal that is heavily rimed 1449 Snow sample #18 (video counter 5345-5445): Bullet rosette and heavily rimed particles Needle rosette 1450 Very light snow falling which is made up of very small crystals. Winds are very light. Snow is hard to identify. It is very heavily rimed particles. Typical size is 0.5 mm. 1540 Very light now falling from the NE at this time. Snow sample #19 (video counter 5445-5633): Heavily rimed plate 800 microns dia. Needles approximately 500 microns long Very heavily rimed capped column 750 microns long Capped column Three plates with 20 micron dia. droplets on it. One plate is fully rimed Needles and two plates Needle and dendrite which are rimed Heavily rimed column 1545 Chemistry samples #6a and #6b taken. 1552 LEAVING THE K-BAND SITE TO GO BACK TO NCAR.