ɪnðə lˈæst ˈaɪs ˈeɪdʒ ɐ ɡlˈeɪʃɚ dˈæmd ðə ɹˈɪvɚ wˌɪtʃ ðˈɛn flˈoʊd fɹʌm dˈʌnstəbəl sˈaʊθ ʌv sˈændɹɪdʒ ˌɪntʊ sənt ˈɔːlbənz vˈeɪl, kɹiːˈeɪɾɪŋ ɐ lˈeɪk.
In the last ice age a glacier dammed the river (which then flowed from Dunstable) south of Sandridge into St Albans Vale, creating a lake.