Fig. 1. Area of the former Larsen B Ice Shelf and tributary glaciers and front retreat since ice-shelf collapse. Fronts are color coded: solid grey:03/17/2002; solid black: spring 2002 to fall 2003; solid white: 2003/2004; dashed black: 2004/2005; dashed white: 2005/2006; dashed grey: 2006/2007; dotted black: 10/09/07. Exact dates of images are provided in the caption to Fig. 2. Approximate ground track of the University of Kansas/NASA flight is traced by the white dotted line. A segment of the ICESat orbit used to construct Fig. 3 is drawn across Crane, Mapple, Melville, and Pequod glaciers as a white dashed line. 17 March 2002 MODIS image. AP: Antarctic Peninsula; WS: Weddell Sea; WAIS: West Antarctic Ice Sheet.

Fig. 2. Glacier fronts interpolated to centerlines and for Crane, to the NASA/KU flightline. Image dates are as follows: grey circle: 03/17/2002 (Larsen B collapse); black squares: 11/27/02, 03/20/03; open triangles: 10/02/03, 11/30/03 (except Jorum, which is 12/27/03), 03/30/04; black circles: 11/15/04, 12/13/04, 02/28/05, 04/03/05; open squares: 09/22/05, 01/05/06, 04/01/06; grey triangles: 09/19/06, 09/24/06, 11/18/06, 01/07/07, 03/05/07; open circles: 10/09/07. Cloud cover and poor illumination limit observations of the Green/Evans/Hecktoria front in 2005.

Fig. 3. Surface elevation from ICESat. The satellite ground tracks are within 200 m and cross the glaciers nearly at right angles to their long axes. The cross just downstream of point ‘B’ in Fig. 5 shows the Crane Glacier crossing. Datesof acquisition are 10/23/03, 10/10/04, 10/28/05, 10/31/06.

Fig. 4. Time series of QuikSCAT backscatter. Crane Glacier samples are from above 1000 m (grey line) and below 500 m (black line). Elevation in the plateau test patch range from 1500 to 1700 m above sea level.

Fig. 5. Upper panel: crane Glacier surface and bed elevation along the KU/NASA flightline. A portion of the bed elevation is missing due to attenuation of the radar signal (presumably due to crevassing). For purposes of illustration, we invert surface elevation and velocity for bed elevation through this region, using Eqs. (1) and (2) and a tuned flow-law rate factor. The surface height at the threshold for calving instability, computed using ice and ocean densities of 900 and 1027 kg m^− 3, respectively, and q = 0.15 is plotted using a dashed line. Bedrock highs at A and B are discussed in the text. The inset shows front position over time, following from Fig. 2. Lower panel: Surface speed mapped by image correlation interpolated to the surface trace of the KU/NASA flightline. Errors associated with the quality of the image correlation are plotted at every fifth data point for the observations spanning less than one year. Errors for the longer time intervals are of the same magnitude as the symbol size. The range of computed ice deformation speed is shaded in dark grey.

Fig. 6. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images of the trunk of Crane Glacier on 7 November 2002 and 25 November 2006. Small frames at right are a) mid-trunk in 2002 image, b) same location in 2006, c) right-lateral tributary in 2006 and d) same location in 2006.

Fig. 7. a) Ratio of longitudinal stress to lateral shear stress for a range of width:thickness and surface slope. The contour interval is 0.2. The figure is created by solving the full 3-D momentum balance, , in which σ represents the stress tensor, in a parallel-sided trough with a parabolic cross-section, typical ice properties (discussed elsewhere), and no basal sliding. The ratio is of depth-integrated values at a distance 1/4 the trough width from the margin (the star in panel b). For reference, width:thickness is about 10 and the surface slope is about 0.019 at the downstream end of Crane Glacier. b) Downstream component of velocity in a slice across the model domain, scaled to the maximum speed. The contour interval is 0.2.