After a hurricane goes through its stages and matures, it still can intensify to certain sizes and strengths. Much like that of humans once they're adults. This all depends on the right environmental factors and whether or not it is near land. The Saffir-Simpson Scale is a way to indicate the strength of these storms by their sustained wind speed, and central barometric pressure.
Category/Classification Winds (mph) Pressure (in. of Hg) Damage Category One Hurricane 74-95 mph >=28.94 in. of Hg. minimal damage Category Two Hurricane 96-110 mph 28.50-28.91 in. of Hg significant damage Category Three Hurricane 111-129 mph 27.91-28.47 in. of Hg severe damage Category Four Hurricane 130-156 mph 27.17-27.88 in. of Hg extreme damage Category Five Hurricane >156 mph <27.17 in.of Hg catastrophic damage