While doing laundry tonight, I discovered that my washer was not draining properly and spewed water all over the floor. The drain hose was fine and we drained the washer by using buckets. The drain pipe seems to be blocked.

We poured water down the drain and some of it went down but it started to back up. Short of calling a plumber, is there anything we can do to solve this?
We've only been in this house for 2 months and it was built in 1970.
Many thanks.