Mother Mary Joseph Dallmer, heroine of the Galveston hurricane of 1900, youngest child of Gregory and Mary Anne Dallmer, was born at Oberhausen, Baden, on March 19, 1852. Her mother immigrated with her children to Galveston, Texas, probably in 1858, at the invitation of her two older children there. Mary entered the Ursuline Academy in Galveston as a small child, graduated in 1869, and entered the Ursuline Sisters in the same year. Gifted intellectually and artistically, she was given responsibility in the school and community while very young. She was elected superior in 1891 and oversaw the construction of the new Ursuline Academy.
When the storm of September 8, 1900, struck Galveston, Mother Mary Joseph directed her community to open its buildings to more than a thousand refugees, Black and White, to calm their terror and meet their needs. At the risk of their own lives the nuns pulled many persons from the floodwaters. Mother Mary Joseph ordered them to strip the convent of linens and give up their own wardrobes to clothe the refugees, and to share what food was spared by the tidal wave. For several weeks after the storm she kept the homeless in what was left of the convent buildings. The Houston Post stated at this time in a nationally reprinted story: "A fearful catastrophe like that of September 8 brings out all that there is in a human being...and when all the noblest attributes...are brought out in one individual, and that a woman, mere words become too weak...to do her proper honor. Such a woman is Mother Mary Joseph. She is the heroine of the storm."
In November 1900 she represented the Galveston Ursulines at an international gathering to form the Roman Union of the Order of St. Ursula. She was appointed the first provincial of the Ursuline convents in Texas and Illinois in the new union. In 1907, when she was elected American assistant to the mother general of the order, she moved to Rome. There she died on May 25, 1909. She is buried in Rome, but a cenotaph is located at Ursuline Cemetery in Galveston.