So big that it is affecting the local gravity, as measured by a specialized satellite.
Antarctica Peninsula (south of Tierra del Fuego) is melting almost by the day. And it is only the second largest region of Antarctica melting and contributing to sea level rise.
B. Wouters et al., Dynamic thinning of glaciers on the Southern Antarctic Peninsula. Science 2015. Pay per view → LINK [doi:10.1126/science.aaa5727]
Growing evidence has demonstrated the importance of ice shelf buttressing on the inland grounded ice, especially if it is resting on bedrock below sea level. Much of the Southern Antarctic Peninsula satisfies this condition and also possesses a bed slope that deepens inland. Such ice sheet geometry is potentially unstable. We use satellite altimetry and gravity observations to show that a major portion of the region has, since 2009, destabilized. Ice mass loss of the marine-terminating glaciers has rapidly accelerated from close to balance in the 2000s to a sustained rate of –56 ± 8 gigatons per year, constituting a major fraction of Antarctica’s contribution to rising sea level. The widespread, simultaneous nature of the acceleration, in the absence of a persistent atmospheric forcing, points to an oceanic driving mechanism.
See also the press release at Science Daily.