Instrument: Ski pole, magnaprobe
Uncertainty: 1 cm
File format: There is a directory SNOW, with subdirectories for each 
snow line. Results from each snow survey is in a separate file. All 
files are ASCII comma separated variable format. The first line of 
the file is the date and the second is column headers for position 
along the line (m) and snow depth (cm). Then there is a string of 
position, depth pairs. The filename convention is SXXXDDMM, where 
S stands for snow, XXX is the individual code for each snow line, 
DD is the day, and MM is the month. The codes are MLE - mainline; 
BLT - Baltimore; ATL - Atlanta; TUK - Tuk, MLS - mainline spur; 
and ABS - albedo spur.

At the beginning of the experiment we laid out five survey lines. 
Surveys of snow depth were routinely conducted along these lines 
throughout the SHEBA year. Measurements were made every 1-2 weeks 
from October through May and every other day from June through August. 
The surveys consisted of walking along a line and measuring snow depth 
every one to five meters. Snow depth was measured either manually using 
a graduated ski pole or automatically using a magnaprobe (as pictured). 
Manual measurements were rounded off to the nearest centimeter and 
magnaprobe values were accurate to better than 0.5 cm. Care was taken 
to repeat the surveys along the same lines, but no attempt was made to 
measure at exactly the same points. During summer, pond depths, as well 
as snow depths, were measured along these lines.

Mainline:  This was our longest line at 500 m. It originated at Pittsburgh, 
   extended over the ridge, and continued past Quebec and Seattle. In January 
   1998 the line was lengthened when leads opened and froze between the 100 
   and 400 m marks.  The portion of the line beyond the 150 m mark was lost 
   during the 2 August 1998 breakup event.
Atlanta: A 200-m-long line at a site collocated with the Atlanta Pam station. Aside 
   from a small ridge at the beginning of the line, the terrain here was fairly flat.
Tuk:  This 200-m-long line traversed our Tuk mass balance site going directly over 
   an old ridge at the 50 m mark of the line. The line was intact for most of the year. 
   There were a few areas that melted through in summer, necessitating a couple of detours.
Baltimore:  This was a first year ice site collocated with a PAM station. The ice began 
   growing in late-August 1997 and was only about 35 cm thick at the start of the experiment. 
   A substantial ridge formed at the edge of this line in January 1998.
Cleveland:  The line went through an old eroded rubble field adjacent to the Cleveland 
   PAM station. Cleveland was a short-lived site. The ice broke up in January 1998 
   and the site was abandoned.