  Type I X-ray bursts are produced by thermonuclear runaways that develop on
accreting neutron stars. Once one location ignites, the flame propagates across
the surface of the star. Flame propagation is fundamental in order to
understand burst properties like rise time and burst oscillations. Previous
work quantified the effects of rotation on the front, showing that the flame
propagates as a deflagration and that the front strongly resembles a hurricane.
However the effect of magnetic fields was not investigated, despite the fact
that magnetic fields strong enough to have an effect on the propagating flame
are expected to be present on many bursters. In this paper we show how the
coupling between fluid layers introduced by an initially vertical magnetic
field plays a decisive role in determining the character of the fronts that are
responsible for the Type I bursts. In particular, on a star spinning at 450 Hz
(typical among the bursters) we test seed magnetic fields of $10^{7} - 10^{10}$
G and find that for the medium fields the magnetic stresses that develop during
the burst can speed up the velocity of the burning front, bringing the
simulated burst rise time close to the observed values. By contrast, in a
magnetic slow rotator like IGR J17480--2446, spinning at 11 Hz, a seed field
$\gtrsim 10^9$ G is required to allow localized ignition and the magnetic field
plays an integral role in generating the burst oscillations observed during the
bursts.
