We determined the dynamic tensile strength of ice and ice silicate mixtures at strain rates of ~104 s-1. At these strain rates, ice has a tensile strength of ~17 MPa, and ice-silicate mixtures with 5 and 30 wt % sand content have strengths of ~20 and 22 MPa, respectively. These values lie significantly above tensile strengths of ~1.6 MPa for ice and of ~5-6 MPa for frozen silt, measured at strain rates of ~10-2 to 100 s-1, but markedly below values found for a variety of rocks at comparable strain rates. Results of the present experiments are used to derive parameters for continuum fracturing models in icy media, which are used to determine relations between tensile strength and strain rate, and to predict stress and damage histories as well as size frequency distributions for ice and ice-silicate fragments. It is found that tensile strength &sgr;M is related to strain rate by &sgr;M∝&egr;˙0<0.25-0.3>0 , similar to results obtained for other geological materials. The increase of small fragments relative to larger fragments with increasing strain rate, as predicted by the continuum model, is a result which parallels findings in laboratory impact experiments.