when i got home today, i noticed billows of smoke coming from under my hood. so i got out, and popped it with extinguisher in hand. luckily, it was just steam. once it cleared, i saw that the entire left half of my engine bay was covered in coolant. i traced it to the back of my engine where it sat in a little steaming pool. i looked all over trying to find where it could have leaked from. then, right above the pool, i saw this little hose that had a slice in it (pic below). i squeezed it and it made a hissing sound, but no coolant came out. what is this hose? and is this the source?

this is extremely important because i'm not risking driving my car until this is fixed. so please, anything will help.
edited: found out it was the heater hose, so i guess i'll get a new one.
added: replaced the heater hose for a whole $2, it looks good and runs fine. but it turns out the last owner put in one of those coolant flush pumps and spliced in that red thing but didn't shorten the hose at all. so the hose was too long and ended up being kinked.