  We have simulated the response of a high energy neutrino telescope to the
stream of low energy neutrinos produced by a supernova. The nominal threshold
of such detectors is in the GeV energy range. The passage of a large flux of
MeV neutrinos during a period of seconds will nevertheless be detected as an
excess of single counting rates in all individual optical modules. Detectors
under construction, which consist of roughly 200 modules, will be able to
detect a galactic supernova at or above the 5 $\sigma$ level. The rate of fake
signals is, however, too large for the telescope to serve as a neutrino watch.
Such capability requires detectors with roughly 3 times the number of optical
modules, thus within easy reach of the next generation detectors.
