Snow tire tread comprising incisions and cavities

A tread for a snow tire comprising:

• a plurality of blocks separated by grooves, wherein the blocks are provided with sipe incisions dividing into several parts from a certain depth onwards, referred to as complex sipes, each complex sipe having, when viewed in cross section, a rectilinear first part extending radially from the tread surface of the tread, and a second part extending the first part and comprising at least two branches each having an end,
• cavities, each cavity extending between the branches of a complex sipe, each cavity comprising a bottom situated at the same level as the ends of the branches,
• wherein the cavities and the grooves of the tread are configured so that this the tread has a voids surface ratio at the end of wear greater than or equal to 35%, and that wherein the distance (D) between two branches of two adjacent complex sipes is at least equal to 2 mm.