  We investigate the incidence and properties of ionized gas outflows in a
sample of 52 galaxies with stellar mass between $10^7$ M$_{\odot}$ and $10^9$
M$_{\odot}$ observed with ultra-deep JWST/NIRSpec MSA spectroscopy as part of
the JWST Advanced Deep Extragalactic Survey (JADES). The high-spectral
resolution (R2700) NIRSpec observations allowed us to identify for the first
time the signature of outflows in the rest-frame optical nebular lines in
low-mass galaxies at $z>3$. The incidence fraction of ionized outflows, traced
by broad components, is about 25-40$\%$ depending on the intensity of the
emission lines. The low incidence fraction might be due to both the sensitivity
limit and the fact that outflows are not isotropic but have a limited opening
angle which results in a detection only when this is directed toward our line
of sight. Evidence for outflows increases slightly with stellar mass and
star-formation rate. The median velocity and mass loading factor (i.e., the
ratio between mass outflow rate and star formation rate) of the outflowing
ionized gas are 350 km s$^{-1}$ and $\eta=2.0^{+1.6}_{-1.5}$, respectively.
These are 1.5 and 100 times higher, respectively than the typical values
observed in local dwarf galaxies. These outflows are able to escape the
gravitational potential of the galaxy and enrich the circum-galactic medium
and, potentially, the inter-galactic medium. Our results indicate that outflows
can significantly impact the star formation activity in low-mass galaxies
within the first 2 Gyr of the Universe.
