Safari tabs going blank, can't refresh

I usually have 10-15 tabs open in Safari.

Sometimes a tab (or multiple tabs) will go blank. As in, if I switch to that tab, it will just display a big white rectangle. No content. The title of the tab is correct, and the icon is correct, but there's nothing in the tab. If I refresh the tab, it refreshes a blank page.

There's no URL to copy and paste into a different tab to re-load the content; the URL is blank. (Even though, again, the title of the tab is correct.) If I want to go back to the page the tab was displaying, I have to find it again via Google or whatever. Usually by searching for the title of the tab, which is still visible.

This usually only happens to one tab at a time, all my other tabs are unaffected. Sometimes it happens to two tabs.

Does anybody else have this problem?