<a href='http://books.google.com/books?id=A-VPDhzccz8C&pg=RA1-PA22&dq=%22ice+cracked+up%22&hl=en&sa=X&ei=UOBPT-uAPaqoiQKr2NS0Bg&ved=0CDYQ6AEwAQ#v=onepage&q=%22ice%20cracked%20up%22&f=false' target='_blank' rel='nofollow'>http://books.google.com/books?id=A-VPDhzccz8C&pg=RA1-PA22&dq=%22ice+cracked+up%22&hl=en&sa=X&ei=UOBPT-uAPaqoiQKr2NS0Bg&ved=0CDYQ6AEwAQ#v=onepage&q=%22ice%20cracked%20up%22&f=false</a><br/><br/>"The weather moderated; the ice <span style="background-color:#ffff00;">cracked up</span> and began to push its floes down the river."<br/><br/>How are "ice cracked" and "ice cracked up" different?