Background: Migraine affects more than 1 billion people, with attacks triggered by a variety of factors. Knowledge of environmental triggers for migraine attacks is limited, and has mostly been studied via emergency room (ER) visits. There are significant barriers and delays for attending ER for migraine treatment, which create challenges for estimating causal links to environmental exposures. We assessed whether smartphone app records may have fewer barriers and reduced lags. Methods: American and Canadian participants completed an online survey about their migraine attacks, smartphone app use, and ER visits. Results: Among 308 participants, barriers to visiting ER were similar in both countries, except for financial concerns in the US. About half of participants who attended ER also recorded the attack in a diary or app. Whereas migraine patients often present to ER 7+ days after onset, records in a smartphone app dataset were created within 2 days of onset. Conclusions: Although not all severe migraine attacks are recorded by smartphone users, smartphone app records may have fewer barriers to creation and shorter time lags compared to ER visit records, making them a rich source of data for research on transient neurologic health outcomes and environmental exposures.