HOUSTON -

The day after the tragic Boston marathon bombings, people are using social media to share touching photos and organize memorials.

Memorial runs are popping up all over the country to symbolically finish the race for those who couldn't. At "Run for Boston" on Facebook, you can find races near you if you want to join in.

The day of the explosions, jammed cell towers made it difficult to reach anyone by cell phone in Boston.

Mobile experts say the networks were overloaded. They recommend texting or tweeting to family and friends in emergencies where cell phone traffic is high. One option is to use "Google Person Finder," a tool created by Google to help reach loved ones in an event of a tragedy.

You can type in your information to let people know where you are and if you're okay; and family members can check in and search for you in the event phones are not working.