  A tau-Herculid meteor outburst or even a storm was predicted by several
models to occur around 5~UT on 31~May, 2022 as a consequence of the break-up of
comet 73P/Schwassmann-Wachmann 3 in 1995. The multi-instrument and
multi-station experiment was carried-out within the Czech Republic to cover
possible earlier activity of the shower between 21 and 1 UT on 30/31 May.
Multi-station observations using video and photographic cameras were used for
calculation of the atmospheric trajectories and heliocentric orbits of the
meteors. Their arrival times are used for determination of the shower activity
profile. Physical properties of the meteoroids are evaluated using various
criteria based on meteor heights. Evolution of spectra of three meteors are
studied as well. This annual but poor meteor shower was active for the whole
night many hours before the predicted peak. A comparison with dynamical models
shows that a mix of older material ejected after 1900 and fresh particles
originating from the 1995 comet fragmentation event was observed. Radiant
positions of both groups of meteors were identified and found to be in good
agreement with simulated radiants. Meteoroids with masses between 10 mg and 10
kg were recorded. The mass distribution index was slightly higher than 2. A
study of the physical properties shows that the tau-Herculid meteoroids belong
to the most fragile particles observed ever, especially among higher masses of
meteoroids. Exceptionally bright bolide observed during the dawn represents a
challenge for the dynamical simulations as it is necessary to explain how to
transfer a half metre body to the vicinity of the Earth at the same time as
millimetre sized particles.
