During colder months, dry heat is the most common cause. Using a humidifier can help significantly. During the day, you can apply nasal saline or some type of moisturizer inside the nose to prevent drying. The most common area where one bleeds is the front part if the nasal septum, called Kisselbachs' plexus. Other aggravating factors (in combination) are allergies, or nasal turbulence due to anatomic narrowing (such as a deviated septum). Weather changes can also cause neurologic inflammation that causes blood vessels to become very fragile.

When you have a severe nosebleed, you should pinch your soft fleshy nostrils together for 5 to 10 minutes. Pinching the bridge of your nose won't do anything.