Butterfly Storm

During these few weeks, when I drive in Brisbane, I saw a lot of white dust floating. At first sight, I thought I was worrying my glass is not right and I need to get a new one. But after I looked them in details, they were a group of white butterflies. Yesterday, this problem got more series. I saw them everywhere. Moreover, there is a wind blowing, a huge group of white butterflies came out from a tree. It did not look normal at all.
Fortunately, I read the news from Yahoo. It calls Caper White. This species of butterfly migrates from Western Queensland to our East Coast every year. This kind of situation is entirely normal. That was a bit larger number this year. I think that is fine too and I saw the number of butterflies is reduced.