  Milagro is a water-Cherenkov detector that observes the extended air showers
produced by cosmic gamma rays of energies E>100GeV. The effective area of
Milagro peaks at energies E~10TeV, however it is still large even down to a few
hundred GeV (~10m^2 at 100GeV). The wide field of view (~2sr) and high duty
cycle (>90%) of Milagro make it ideal for continuously monitoring the overhead
sky for transient Very High Energy (VHE) emissions. This study searched the
Milagro data for such emissions. Even though the search was optimized primarily
for detecting the emission from Gamma-Ray Bursts (GRBs), it was still sensitive
to the emission from the last stages of the evaporation of Primordial Black
Holes or to any other kind of phenomena that produce bursts of VHE gamma rays.
Measurements of the GRB spectra by satellites up to few tens of GeV showed no
signs of a cutoff. Even though multiple instruments sensitive to $GeV/TeV$
gamma rays have performed observations of GRBs, there has not yet been a
definitive detection of such an emission yet. One of the reasons for that is
that gamma rays with energies E>~100GeV are attenuated by interactions with the
extragalactic background light or are absorbed internally at the site of the
burst. There are many models that predict VHE gamma-ray emission from GRBs. A
detection or a constraint of such an emission can provide useful information on
the mechanism and environment of GRBs. This study performed a blind search of
the Milagro data of the last five years for bursts of VHE gamma rays with
durations ranging from 100musec to 316sec. No GRB localization was provided by
an external instrument. Instead, the whole dataset was thoroughly searched in
time, space, and duration. No significant events were detected. Upper limits
were placed on the VHE emission from GRBs.
